usb: renesas_usbhs: fix __le16 warnings

Fix the warnings generated by casting to/from __le16 without
using the correct functions.

Fixes the following sparse warnings:

drivers/usb/renesas_usbhs/common.c:165:25: warning: incorrect type in assignment (different base types)
drivers/usb/renesas_usbhs/common.c:165:25:    expected restricted __le16 [usertype] wValue
drivers/usb/renesas_usbhs/common.c:165:25:    got unsigned short
drivers/usb/renesas_usbhs/common.c:166:25: warning: incorrect type in assignment (different base types)
drivers/usb/renesas_usbhs/common.c:166:25:    expected restricted __le16 [usertype] wIndex
drivers/usb/renesas_usbhs/common.c:166:25:    got unsigned short
drivers/usb/renesas_usbhs/common.c:167:25: warning: incorrect type in assignment (different base types)
drivers/usb/renesas_usbhs/common.c:167:25:    expected restricted __le16 [usertype] wLength
drivers/usb/renesas_usbhs/common.c:167:25:    got unsigned short
drivers/usb/renesas_usbhs/common.c:173:39: warning: incorrect type in argument 3 (different base types)
drivers/usb/renesas_usbhs/common.c:173:39:    expected unsigned short [usertype] data
drivers/usb/renesas_usbhs/common.c:173:39:    got restricted __le16 [usertype] wValue
drivers/usb/renesas_usbhs/common.c:174:39: warning: incorrect type in argument 3 (different base types)
drivers/usb/renesas_usbhs/common.c:174:39:    expected unsigned short [usertype] data
drivers/usb/renesas_usbhs/common.c:174:39:    got restricted __le16 [usertype] wIndex
drivers/usb/renesas_usbhs/common.c:175:39: warning: incorrect type in argument 3 (different base types)
drivers/usb/renesas_usbhs/common.c:175:39:    expected unsigned short [usertype] data

Note. I belive this to be correct, and should be a no-op on arm.

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>