usb: gadget: f_hid: {GET,SET} PROTOCOL Support

The current f_hid driver doesn't handle GET_PROCOTOL and
SET_PROCOTOL requests, which are required to operate HID
gadgets in BOOT mode. This patch implements this feature for
devices that have the same implementation for REPORT and BOOT mode
so that these devices are recognized by older BIOSes.

Signed-off-by: Abdulhadi Mohamed <abdulahhadi2@gmail.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>