msm: move types and declarations to header file

Move all function declarations and types to the header
file to make the macros and definitions available even
when the CONFIG_MSM_SECURE_BUFFER is not enabled. Rename
rid of the msm_ion_secure_table and msm_ion_unsecure_table
to something more generic.

Change-Id: Ia5ca0c52f971a67c7936c64b42cd2522aa1773fa
Signed-off-by: Neeti Desai <neetid@codeaurora.org>