staging: vt6656: rxtx.c dead code TYPE_ATIMDMA/TYPE_BEACONDMA

Both TYPE_ATIMDMA/TYPE_BEACONDMA are not used in driver for the value of uDMAIdx.

Remove dead code.

Signed-off-by: Malcolm Priestley <tvboxspy@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>