msm: kgsl: Report error if regulator enable fails

In function kgsl_pwrctrl_pwrrail check if call to enable the
regulator fails or not and report an error message on failure.

Change-Id: Ib729bbbeb544c572f1d43771e5777a951346e876
Signed-off-by: Shubhraprakash Das <sadas@codeaurora.org>
diff --git a/drivers/gpu/msm/kgsl_pwrctrl.c b/drivers/gpu/msm/kgsl_pwrctrl.c
index 2aaefba..6854d6c 100644
--- a/drivers/gpu/msm/kgsl_pwrctrl.c
+++ b/drivers/gpu/msm/kgsl_pwrctrl.c
@@ -443,8 +443,12 @@
 		if (!test_and_set_bit(KGSL_PWRFLAGS_POWER_ON,
 			&pwr->power_flags)) {
 			trace_kgsl_rail(device, state);
-			if (pwr->gpu_reg)
-				regulator_enable(pwr->gpu_reg);
+			if (pwr->gpu_reg) {
+				int status = regulator_enable(pwr->gpu_reg);
+				if (status)
+					KGSL_DRV_ERR(device, "regulator_enable "
+							"failed: %d\n", status);
+			}
 		}
 	}
 }