fbdev: xoffset, yoffset and yres are unsigned

The xoffset, yoffset and yres members of fb_var_screeninfo are __u32.
Make them unsigned in the code as well.
Signed-off-by: Ville Syrjala <syrjala@sci.fi>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Cc: Krzysztof Helt <krzysztof.h1@poczta.fm>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/video/fbmem.c

@@ -848,9 +848,8 @@ int
 fb_pan_display(struct fb_info *info, struct fb_var_screeninfo *var)
 {
 	struct fb_fix_screeninfo *fix = &info->fix;
-        int xoffset = var->xoffset;
-        int yoffset = var->yoffset;
-        int err = 0, yres = info->var.yres;
+	unsigned int yres = info->var.yres;
+	int err = 0;
 
 	if (var->yoffset > 0) {
 		if (var->vmode & FB_VMODE_YWRAP) {
@@ -866,8 +865,8 @@ fb_pan_display(struct fb_info *info, struct fb_var_screeninfo *var)
 				 (var->xoffset % fix->xpanstep)))
 		err = -EINVAL;
 
-        if (err || !info->fbops->fb_pan_display || xoffset < 0 ||
-	    yoffset < 0 || var->yoffset + yres > info->var.yres_virtual ||
+	if (err || !info->fbops->fb_pan_display ||
+	    var->yoffset + yres > info->var.yres_virtual ||
 	    var->xoffset + info->var.xres > info->var.xres_virtual)
 		return -EINVAL;