msm: camera: Fix AXI HALT issue

At the time of camera stop, vfe driver sets
AXI HALT and needs to  wait for HALT_ACK bit
is set. In the driver this logic was missed and
used to wait for 500 secs. Update VFE driver with
this logic to fix the delay in AXI Halt.

Change-Id: I55626586921816eda31df7a75a27f467c669bd7f
Signed-off-by: Suresh Vankadara <svankada@codeaurora.org>