media: rc: add keymap for Khadas VIM/EDGE remote

Khadas VIM and Edge SBC devices use the same NEC remote device. The
remote includes a mouse button for Android use. This has been mapped
to KEY_MUTE.

Signed-off-by: Christian Hewitt <christianshewitt@gmail.com>
Signed-off-by: Sean Young <sean@mess.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>