staging: sm750fb: use BIT macro for DMA_ABORT_INTERRUPT single-bit fields

Replace complex definition of DMA_ABORT_INTERRUPT register fields with
BIT() macro and use open-coded implementation for register manipulation

Signed-off-by: Mike Rapoport <mike.rapoport@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>