loki: Do not turn on CAM_MCLK for FFD fab >= a3

loki: Do not turn on CAM_MCLK for FFD fab >= a3

Move Camera clock from tegra to external xtal for
loki ffd fab a3 or higher

Bug 1429817

Change-Id: Ic4a617ba779181d5af5dda8a7754591b07e2ab22
Signed-off-by: Frank Chen <frankc@nvidia.com>
Reviewed-on: http://git-master/r/375122
(cherry picked from commit ac5c21ec4037ca9436e27ab96201e6e8c91ff2ab)
Reviewed-on: http://git-master/r/377316
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Gary Fitzer <gfitzer@nvidia.com>
Reviewed-by: Siddardha Naraharisetti <siddardhan@nvidia.com>
Reviewed-by: Raymond Poudrier <rapoudrier@nvidia.com>