freescale DIU: bug fix: add sanity check for AOI position

AOI position cannot be negative.

Signed-off-by: York Sun <yorksun@freescale.com>
Cc: Kumar Gala <galak@gate.crashing.org>
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/fsl-diu-fb.c

@@ -479,6 +479,10 @@ static void adjust_aoi_size_position(struct fb_var_screeninfo *var,
 	base_plane_width = machine_data->fsl_diu_info[0]->var.xres;
 	base_plane_height = machine_data->fsl_diu_info[0]->var.yres;
 
+	if (mfbi->x_aoi_d < 0)
+		mfbi->x_aoi_d = 0;
+	if (mfbi->y_aoi_d < 0)
+		mfbi->y_aoi_d = 0;
 	switch (index) {
 	case 0:
 		if (mfbi->x_aoi_d != 0)