gma500: Re-order checks and dereferences in psb_intel_lvds

Dan Carpenter reports:

Smatch complains about 6a7afe3 "gma500: continue abstracting
platform specific code"

drivers/staging/gma500/psb_intel_lvds.c +579 psb_intel_lvds_set_property(7)
	warn: variable dereferenced before check 'encoder'

	--- a/drivers/staging/gma500/psb_intel_lvds.c
	+++ b/drivers/staging/gma500/psb_intel_lvds.c
	@@ -575,11 +575,12 @@ int psb_intel_lvds_set_property(struct drm_connector *connector,
					       struct drm_property *property,
					       uint64_t value)
	 {
	-       struct drm_encoder *pEncoder = connector->encoder;
	+       struct drm_encoder *encoder = connector->encoder;
	+       struct drm_psb_private *dev_priv = encoder->dev->dev_private;
						   ^^^^^^^^^^^^
dereference encoder here.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/gma500/psb_intel_lvds.c

@@ -574,9 +574,14 @@ int psb_intel_lvds_set_property(struct drm_connector *connector,
 				       uint64_t value)
 {
 	struct drm_encoder *encoder = connector->encoder;
-	struct drm_psb_private *dev_priv = encoder->dev->dev_private;
+	struct drm_psb_private *dev_priv;
+
+	if (!encoder)
+	        return -1;
 
-	if (!strcmp(property->name, "scaling mode") && encoder) {
+	dev_priv = encoder->dev->dev_private;
+
+	if (!strcmp(property->name, "scaling mode")) {
 		struct psb_intel_crtc *pPsbCrtc =
 					to_psb_intel_crtc(encoder->crtc);
 		uint64_t curValue;
@@ -617,7 +622,7 @@ int psb_intel_lvds_set_property(struct drm_connector *connector,
 						      encoder->crtc->fb))
 				goto set_prop_error;
 		}
-	} else if (!strcmp(property->name, "backlight") && encoder) {
+	} else if (!strcmp(property->name, "backlight")) {
 		if (drm_connector_property_set_value(connector,
 							property,
 							value))
@@ -631,7 +636,7 @@ int psb_intel_lvds_set_property(struct drm_connector *connector,
                         }
 #endif
 		}
-	} else if (!strcmp(property->name, "DPMS") && encoder) {
+	} else if (!strcmp(property->name, "DPMS")) {
 		struct drm_encoder_helper_funcs *pEncHFuncs
 						= encoder->helper_private;
 		pEncHFuncs->dpms(encoder, value);