V4L/DVB (8534): remove select's of FW_LOADER

After commit d9b19199
(always enable FW_LOADER unless EMBEDDED=y) we can remove
the FW_LOADER select's and corresponding dependencies
on HOTPLUG.

Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>