drm/amd/powerplay: fix boolreturn.cocci warnings

BugLink: http://bugs.launchpad.net/bugs/1546572

drivers/gpu/drm/amd/amdgpu/../powerplay/hwmgr/ppatomctrl.c:475:10-11: WARNING: return of 0/1 in function 'atomctrl_lookup_gpio_pin' with return type bool

 Return statements in functions returning bool should use
 true/false instead of 1/0.
Generated by: scripts/coccinelle/misc/boolreturn.cocci

CC: yanyang1 <young.yang@amd.com>
Signed-off-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 195567e9)
Signed-off-by: Alberto Milone <alberto.milone@canonical.com>
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

drivers/gpu/drm/amd/powerplay/hwmgr/ppatomctrl.c

@@ -521,13 +521,13 @@ static bool atomctrl_lookup_gpio_pin(
 				pin_assignment->ucGpioPinBitShift;
 			gpio_pin_assignment->us_gpio_pin_aindex =
 				le16_to_cpu(pin_assignment->usGpioPin_AIndex);
-			return 0;
+			return false;
 		}
 
 		offset += offsetof(ATOM_GPIO_PIN_ASSIGNMENT, ucGPIO_ID) + 1;
 	}
 
-	return 1;
+	return true;
 }
 
 /**