[media] dvb-usb/it913x: multi firmware loader

Multi firmware loader
 This uses scatter write firmware headers
 The firmware must start with 03 XX 00
 and be the extract firmware length.

 I have tried all available firmwares with this loader.

Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>