[media] ati_remote: Generalize KIND_ACCEL to accept diagonals

Rather than having special code cases for diagonal mouse
movements, extend the general purpose code used for the
cardinal directions to handle arbitrary (x,y) deltas.

The deltas themselves are stored in translation table's "code"
field; this is also progress toward the goal of eliminating
the "value" element entirely.

Signed-off-by: George Spelvin <linux@horizon.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>