fsl: rename 'dma' to 'brdcfg1' in the ngPIXIS structure

The ngPIXIS is a board-specific FPGA, but the definition of the registers
is mostly consistent.  On boards where it matter, register 9 is called
'brdcfg1' instead of 'dma', so rename the variable in the ngpixis_t
definition.

Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>