msm: camera: enable 3 RDI path work concurrently

If we use 3 RDI path concurrently, and the lower 8bit of
stream_cfg_cmd->axi_stream_handle is assigned to
stream_cfg_cmd->stream_src whose value is 7,in this case, the function
msm_isp_validate_axi_request() will return error.

Change-Id: I1c73192a22cc29c5743618cdc961794e1549657b
Signed-off-by: Tao Jiang <taojiang@codeaurora.org>