ASoC: mxs-saif: remove mach header inclusion

The header <mach/hardware.h> is not needed at all, and <mach/mxs.h> is
needed only for macros MXS_SET_ADDR and MXS_CLR_ADDR.  Define the macros
and remove the mach header inclusions.

Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>