Camera3: Change max inflight requests to 5

Maximum inflight request has direct impact on latency such
as shutter lag. Even if the real camera pipeline delay is
5, whenever HAL misses a request on SOF boundary, more requests
are accumulated in HAL. And eventually maximum number of
requests will be in flight.

Profiling shows saving of 100ms when changed from 7 to 5.

Bug: 10712902
Change-Id: Ib00d58a6045f8f545f127ec97f2800f8e3c9dfe6

QCamera2/HAL3/QCamera3Channel.cpp

@@ -702,7 +702,7 @@ void QCamera3RegularChannel::putStreamBufs()
     mMemory = NULL;
 }
 
-int QCamera3RegularChannel::kMaxBuffers = 7;
+int QCamera3RegularChannel::kMaxBuffers = 5;
 
 QCamera3MetadataChannel::QCamera3MetadataChannel(uint32_t cam_handle,
                     mm_camera_ops_t *cam_ops,