usb: xhci: make USB_XHCI_PLATFORM selectable
usb: xhci: make USB_XHCI_PLATFORM selectable

Right now xhci-plat-hcd can be built when using one of platform specific
drivers only (mvebu/rcar). There shouldn't be such limitation as some
platforms may not require any quirks and may want to just use a generic
driver ("generic-xhci" / "xhci-hcd").

Signed-off-by: Rafał Miłecki <dced371c11179e2cb83b1e305b9d7b15f379452b@gmail.com>
Signed-off-by: Mathias Nyman <2d4473c5e67eb83655334d4e9a7757f781607241@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <4645f7897fd33786a2ee1264d590b3c400559d85@linuxfoundation.org>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs