platform/x86: intel_pmc_ipc: Convert to MFD

This driver only creates a bunch of platform devices sharing resources
belonging to the PMC device. This is pretty much what MFD subsystem is
for so move the driver there, renaming it to intel_pmc_bxt.c which
should be more clear what it is.

MFD subsystem provides nice helper APIs for subdevice creation so
convert the driver to use those. Unfortunately the ACPI device includes
separate resources for most of the subdevices so we cannot simply call
mfd_add_devices() to create all of them but instead we need to call it
separately for each device.

The new MFD driver continues to expose two sysfs attributes that allow
userspace to send IPC commands to the PMC/SCU to avoid breaking any
existing applications that may use these. Generally this is bad idea so
document this in the ABI documentation.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/usb/typec/tcpm/Kconfig

@@ -41,8 +41,8 @@ config TYPEC_FUSB302
 config TYPEC_WCOVE
 	tristate "Intel WhiskeyCove PMIC USB Type-C PHY driver"
 	depends on ACPI
+	depends on MFD_INTEL_PMC_BXT
 	depends on INTEL_SOC_PMIC
-	depends on INTEL_PMC_IPC
 	depends on BXT_WC_PMIC_OPREGION
 	help
 	  This driver adds support for USB Type-C on Intel Broxton platforms