ARM: OMAP2+: AM33XX: CM/PRM: Use __ASSEMBLER__ macros in header files

This is necessary to ensure that macros declared here can
be reused from assembly files.

Signed-off-by: Vaibhav Bedia <vaibhav.bedia@ti.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Acked-by: Peter Korsgaard <jacmet@sunsite.dk>
Signed-off-by: Paul Walmsley <paul@pwsan.com>