OMAP: DSS2: OMAPFB: Fix sysfs mirror input check

Using bool silently converted input to 0 or 1, making the range check
useless. Use unsigned long instead, and convert to bool later. Found by
Coverity.

Signed-off-by: Jani Nikula <ext-jani.1.nikula@nokia.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@nokia.com>
diff --git a/drivers/video/omap2/omapfb/omapfb-sysfs.c b/drivers/video/omap2/omapfb/omapfb-sysfs.c
index 51c13c3..6f9c72c 100644
--- a/drivers/video/omap2/omapfb/omapfb-sysfs.c
+++ b/drivers/video/omap2/omapfb/omapfb-sysfs.c
@@ -102,7 +102,7 @@
 {
 	struct fb_info *fbi = dev_get_drvdata(dev);
 	struct omapfb_info *ofbi = FB2OFB(fbi);
-	bool mirror;
+	unsigned long mirror;
 	int r;
 	struct fb_var_screeninfo new_var;