Add arm msm maintainer entry

This adds a maintainer entry for the arch/arm/mach-msm sub-architecture and
all it's components in various locations.

Signed-off-by: David Brown <davidb@codeaurora.org>
Signed-off-by: Bryan Huntsman <bryanh@codeaurora.org>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>