[media] media: rc: add raw decoder for Sharp protocol

Add a raw decoder for the Sharp protocol. It uses a pulse distance
modulation with a pulse of 320us and a bit period of 2ms for a logical 1
and 1ms for a logical 0. The first part of the message consists of a
5-bit address, an 8-bit command, and two other bits, followed by a 40ms
gap before the echo message which is an inverted version of the main
message except for the address bits.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Mauro Carvalho Chehab <m.chehab@samsung.com>
Cc: linux-media@vger.kernel.org
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>