soc: qcom: mem-buf: Do not assume VMID values

The mem-buf code currently assumes that the VMID values
for the VMs are known up-front, which may not be the case
when VMIDs are allocated dynamically. Thus, remove all
such assumptions, and query the resource manager driver
for VMID values. Also, rename the MEM_BUF_VMID_HLOS identifier
to MEM_BUF_VMID_PRIMARY_VM so as to not tie HLOS to the role
of primary VM.

Change-Id: I4cd79e31d7bda6d1437e690ac0e63b15a69565ef
Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>