V4L/DVB: Kworld 315U remote support

Adds remote support for the Kworld 315U device

I have added the change for the IR_TYPE_NEC that Mauro suggested.

Note: I believe I got most of the mappings correct.  Though the
source and shutdown button probably could be mapped to something
better.

[mchehab@redhat.com: Fix CodingStyle]
Signed-off-by: Franklin Meng <fmeng2002@yahoo.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>