mailbox: msm_qmp: Fix message send to AOP

QMP state resetting in freeze callback is causing
clock vote failures for Jtag-etm driver from thaw
callback which is running after freeze call back.
Move state reset code to restore callback to allow
clients to use AOP communication after freeze call back.

Change-Id: I1719af6179342d01596d7bd4a771a041cf6e7b53
Signed-off-by: Arun Prakash <app@codeaurora.org>