msm: kgsl: Handle a possible ringbuffer allocspace error

In the GPU specific start functions, account for the possibility
that ringbuffer allocation routine might return NULL.

Change-Id: Ic0dedbadf6199fee78b6a8c8210a1e76961873a0
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
diff --git a/drivers/gpu/msm/adreno_ringbuffer.c b/drivers/gpu/msm/adreno_ringbuffer.c
index 37960d6..282b986 100644
--- a/drivers/gpu/msm/adreno_ringbuffer.c
+++ b/drivers/gpu/msm/adreno_ringbuffer.c
@@ -440,7 +440,9 @@
 	adreno_regwrite(device, REG_CP_ME_CNTL, 0);
 
 	/* ME init is GPU specific, so jump into the sub-function */
-	adreno_dev->gpudev->rb_init(adreno_dev, rb);
+	status = adreno_dev->gpudev->rb_init(adreno_dev, rb);
+	if (status)
+		return status;
 
 	/* idle device to validate ME INIT */
 	status = adreno_idle(device);