media: uvcvideo: Refactor frame parsing code into a uvc_parse_frame function

The ftype value does not change in the while loop so we can check it
before entering the while loop. Refactoring the frame parsing code into
a dedicated uvc_parse_frame function makes this more readable.

Signed-off-by: Benoit Sevens <bsevens@google.com>
Link: https://lore.kernel.org/r/20241107142204.1182969-3-bsevens@google.com


Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>