fbdev: omap2: fix inconsistent lock returns in omapfb_mmap

Fix the warning about inconsistent returns for '&rg->lock' in
omapfb_mmap() function. The warning arises because the error path
uses 'ofbi->region' while the normal path uses 'rg'.

smatch warnings:
drivers/video/fbdev/omap2/omapfb/omapfb-main.c:1126 omapfb_mmap()
warn: inconsistent returns '&rg->lock'.

Reported-by: kernel test robot <[email protected]>
Signed-off-by: Hongling Zeng <[email protected]>
Signed-off-by: Helge Deller <[email protected]>

Author: zenghongling0719

drivers/video/fbdev/omap2/omapfb/omapfb-main.c

@@ -1121,7 +1121,7 @@ static int omapfb_mmap(struct fb_info *fbi, struct vm_area_struct *vma)
 	return 0;
 
 error:
-	omapfb_put_mem_region(ofbi->region);
+	omapfb_put_mem_region(rg);
 
 	return r;
 }