msm: camera: Fix live snapshot issue

In case of live snasphot, buffer is not returned from ISP to HAL in
scenario where preview buffer queue starves. This happens because rc
take negative value while iterating into composite_irq loop. Even
though live snapshot buffer is available, since rc is not reset, error
case is taken for all subsequent loops. Reset rc to fix the issue.

Change-Id: Ice5afbe320feab4da1f8b1737be580da36bfcaa8
Signed-off-by: Sreesudhan Ramakrish Ramkumar <srramku@codeaurora.org>