msm: kgsl: Use a common sharedmem init function

Since we initialize the kgsl sharedmem structures from various
places, use a common function to avoid code duplication.

Change-Id: I5953dc44f4fbd89ce57dffe933369f58a6c19bde
Signed-off-by: Lynus Vaz <lvaz@codeaurora.org>
4 files changed