ARM: msm: Move dma.h #defines that are private to dma.c

These #defines are only used by the dma.c file within mach-msm.
Don't put them into a global mach include that any driver can use
to muck with registers within the dma controller. This also
prevents random people from getting access to msm_iomap.h
(a file that will soon be private to mach-msm).

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: David Brown <davidb@codeaurora.org>