V4L/DVB (13716): [Mantis] Bug: incorrect byte swap

You know, the worst endianness errors are not the cases where
people forget to byte-swap, but the cases where they either byte-swap
with the wrong size, or byte-swap when they shouldn't have done so at
all. Those ones defeat the casual reader of the code.

Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Manu Abraham <manu@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>