msm: ipa4: Fix to decrement the client count after writing QMAP ID

couple of code changes,

- Observing the client count mismatch because not decrementing the
  client count after updating QMAP ID.Added changes to decrement the
  client count after updating client count.

- Before decrement the client count, resetting endpoint context
  it leads to invalid client count value was decrementing. Added changes
  to reset the client endpoint structure after decrement the client count.

Change-Id: I9154ce0ff2da2687735d56622de0d6980d23cf66
Acked-by: Ashok Vuyyuru <avuyyuru@qti.qualcomm.com>
Signed-off-by: Mohammed Javid <mjavid@codeaurora.org>