v4l1: fix 32-bit compat microcode loading translation

The compat code for the VIDIOCSMICROCODE ioctl is totally buggered.
It's only used by the VIDEO_STRADIS driver, and that one is scheduled to
staging and eventually removed unless somebody steps up to maintain it
(at which point it should use request_firmware() rather than some magic
ioctl).  So we'll get rid of it eventually.

But in the meantime, the compatibility ioctl code is broken, and this
tries to get it to at least limp along (even if Mauro suggested just
deleting it entirely, which may be the right thing to do - I don't think
the compatibility translation code has ever worked unless you were very
lucky).

Reported-by: Kees Cook <kees.cook@canonical.com>
Cc: Mauro Carvalho Chehab <mchehab@infradead.org>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>