msm: ADSPRPC: Restrict access to hyp_assign_phys calls

Block hyp_assign_phys calls, if the restrict access
flag is defined in the device specific file.

Change-Id: Ie546e748169dda51af4ab5f017581bbda2cc7081
Signed-off-by: Tharun Kumar Merugu <mtharu@codeaurora.org>