phy: omap-usb2: move omap_usb.h from linux/usb/ to linux/phy/

No functional change. Moved omap_usb.h from linux/usb/ to linux/phy/.
Also removed the unused members of struct omap_usb (after phy-omap-pipe3
started using it's own header file)

Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>

drivers/phy/phy-omap-usb2.c

@@ -21,7 +21,7 @@
 #include <linux/slab.h>
 #include <linux/of.h>
 #include <linux/io.h>
-#include <linux/usb/omap_usb.h>
+#include <linux/phy/omap_usb.h>
 #include <linux/usb/phy_companion.h>
 #include <linux/clk.h>
 #include <linux/err.h>