msm: ADSPRPC: Use remote virtual address range to lookup mappings

The virtual address being received when the mappings are to
be removed are that of the remote processor and look up using
the appropriate field while searching for the mappings.

Change-Id: I855b5307f07aae98914cedda6f201f00afb92f28
Signed-off-by: Sathish Ambley <sathishambley@codeaurora.org>