msm: camera: solve twice request MCLK GPIO for camera

In 8x26 MTP/QRD design, main/front camera sensor shares
the same MCLK GPIO, the poweron may fails in some cases
Change the process to output a error message for driver
bringup state to make sure other gpio are handled properly.

Change-Id: I48ee01f32ae5d7e02d3efe8578a747f23a6d8a71
Signed-off-by: Su Liu <suliu@codeaurora.org>