msm: kgsl: Call adreno_init only once on startup

The adreno_init function initializes things that need to be initialized
only once on the first start up. After that until the device is removed
the adreno_init function does not need to called again. Make changes
to execute this function just once until the device is removed.

Change-Id: I1bd18dd9ec70146dc74da1ee9ad1186576344309
Signed-off-by: Shubhraprakash Das <sadas@codeaurora.org>