msm: camera: Fix for dual ISP buffer management

Return -1 when there is no free buffer for dual ISP use case,
in order to have proper error handling in isp driver..

Change-Id: Ic3f3261bebe192fdcf62a1d06f4e8a1e6033ef61
Signed-off-by: Kevin Chan <ktchan@codeaurora.org>
1 file changed