media: tegra: as364x: separate flash level support

media: tegra: as364x: separate flash level support

similar to max77665 & max77387 - each led can be set individually.
added mutex protection in i2c access and power on/off functions to
prevent race conditions.
also added i2c dump function to trace i2c traffic.
code optimization.

bug 1231420

Change-Id: I9f0c3b164925b2a356b41abf6c3e770c79578184
Signed-off-by: Charlie Huang <chahuang@nvidia.com>
Reviewed-on: http://git-master/r/197732
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Bharat Nihalani <bnihalani@nvidia.com>