firmware: qcom: scm: Split out 32-bit specific SCM code

Split out the 32-bit SCM implementation into its own file to prep for
supporting a 64-bit/ARM64 implementation as well.  We create a simple shim
to ensure both versions conform to the same interface.

Signed-off-by: Kumar Gala <galak@codeaurora.org>

diff --cc drivers/firmware/Makefile
Simple merge

diff --cc drivers/firmware/qcom_scm-32.c
Simple merge

diff --cc drivers/firmware/qcom_scm.c
Simple merge

diff --cc drivers/firmware/qcom_scm.h
Simple merge