V4L/DVB (3657): Kconfig: Add firmware download comments for or51211 and or51132

- Added firmware download comments to or51211 and or51132 Kconfig help text.

Signed-off-by: Trent Piepho <xyzzy@speakeasy.org>
Signed-off-by: Michael Krufky <mkrufky@linuxtv.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>