msm: kgsl: Lower bounds check the number of power levels

A misconfigured board file could cause an out-of-bounds
array access through this value.

Change-Id: I64bbad0c096a2efe65376991537d810141370d72
CRs-Fixed: 439230
Signed-off-by: Lucille Sylvester <lsylvest@codeaurora.org>
diff --git a/drivers/gpu/msm/kgsl_pwrctrl.c b/drivers/gpu/msm/kgsl_pwrctrl.c
index 3b9b689..b6b024e 100644
--- a/drivers/gpu/msm/kgsl_pwrctrl.c
+++ b/drivers/gpu/msm/kgsl_pwrctrl.c
@@ -878,7 +878,8 @@
 	if (pdata->set_grp_async != NULL)
 		pdata->set_grp_async();
 
-	if (pdata->num_levels > KGSL_MAX_PWRLEVELS) {
+	if (pdata->num_levels > KGSL_MAX_PWRLEVELS ||
+	    pdata->num_levels < 1) {
 		KGSL_PWR_ERR(device, "invalid power level count: %d\n",
 					 pdata->num_levels);
 		result = -EINVAL;