USB: add SPDX identifiers to all remaining files in drivers/usb/

It's good to have SPDX identifiers in all files to make it easier to
audit the kernel tree for correct licenses.

Update the drivers/usb/ and include/linux/usb* files with the correct
SPDX license identifier based on the license text in the file itself.
The SPDX identifier is a legally binding shorthand, which can be used
instead of the full boiler plate text.

This work is based on a script and data from Thomas Gleixner, Philippe
Ombredanne, and Kate Stewart.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kate Stewart <kstewart@linuxfoundation.org>
Cc: Philippe Ombredanne <pombredanne@nexb.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Acked-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/dwc3/core.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /**
  * core.c - DesignWare USB3 DRD Controller Core file
  *

drivers/usb/dwc3/core.h

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * core.h - DesignWare USB3 DRD Core Header
  *

drivers/usb/dwc3/debug.h

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /**
  * debug.h - DesignWare USB3 DRD Controller Debug Header
  *

drivers/usb/dwc3/debugfs.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /**
  * debugfs.c - DesignWare USB3 DRD Controller DebugFS file
  *

drivers/usb/dwc3/drd.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /**
  * drd.c - DesignWare USB3 DRD Controller Dual-role support
  *

drivers/usb/dwc3/dwc3-exynos.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /**
  * dwc3-exynos.c - Samsung EXYNOS DWC3 Specific Glue layer
  *

drivers/usb/dwc3/dwc3-keystone.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /**
  * dwc3-keystone.c - Keystone Specific Glue layer
  *

drivers/usb/dwc3/dwc3-of-simple.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /**
  * dwc3-of-simple.c - OF glue layer for simple integrations
  *

drivers/usb/dwc3/dwc3-omap.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /**
  * dwc3-omap.c - OMAP Specific Glue layer
  *

drivers/usb/dwc3/dwc3-pci.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /**
  * dwc3-pci.c - PCI Specific glue layer
  *

drivers/usb/dwc3/dwc3-st.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0+
 /**
  * dwc3-st.c Support for dwc3 platform devices on ST Microelectronics platforms
  *

drivers/usb/dwc3/ep0.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * ep0.c - DesignWare USB3 DRD Controller Endpoint 0 Handling
  *

drivers/usb/dwc3/gadget.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * gadget.c - DesignWare USB3 DRD Controller Gadget Framework Link
  *

drivers/usb/dwc3/gadget.h

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * gadget.h - DesignWare USB3 DRD Gadget Header
  *

drivers/usb/dwc3/host.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /**
  * host.c - DesignWare USB3 DRD Controller Host Glue
  *

drivers/usb/dwc3/io.h

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /**
  * io.h - DesignWare USB3 DRD IO Header
  *

drivers/usb/dwc3/trace.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /**
  * trace.c - DesignWare USB3 DRD Controller Trace Support
  *

drivers/usb/dwc3/trace.h

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /**
  * trace.h - DesignWare USB3 DRD Controller Trace Support
  *

drivers/usb/dwc3/ulpi.c

@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /**
  * ulpi.c - DesignWare USB3 Controller's ULPI PHY interface
  *