usb: gadget: f_fs: Add support for CCID descriptors.

Nothing to remap, only check length.
Define a minimal structure for CCID descriptor only used to check length.
As this descriptor shares the same value as HID descriptors, keep track and
compare current interface's class to expected HID and CCID standard values.

Signed-off-by: Vincent Pelletier <plr.vincent@gmail.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>