blackfin video driver: fix bug when opening/reading/mmaping BF54x and BF52x framebuffer simultaneously

http://blackfin.uclinux.org/gf/project/uclinux-dist/tracker/?action=TrackerItemEdit&tracker_item_id=3974

opening/reading/mmaping BF54x and BF52x framebuffer simultaneously triggers
BUG: failure at mm/nommu.c:470/add_nommu_vma() Add VM_SHARED to the default
vm_flags

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/video/bf54x-lq043fb.c

@@ -384,7 +384,7 @@ static int bfin_bf54x_fb_mmap(struct fb_info *info, struct vm_area_struct *vma)
 	 *   Other flags can be set, and are documented in
 	 *   include/linux/mm.h
 	 */
-	vma->vm_flags |= VM_MAYSHARE;
+	vma->vm_flags |=  VM_MAYSHARE | VM_SHARED;
 
 	return 0;
 }

drivers/video/bfin-t350mcqb-fb.c

@@ -302,7 +302,7 @@ static int bfin_t350mcqb_fb_mmap(struct fb_info *info, struct vm_area_struct *vm
 	 *   Other flags can be set, and are documented in
 	 *   include/linux/mm.h
 	 */
-	vma->vm_flags |= VM_MAYSHARE;
+	vma->vm_flags |= VM_MAYSHARE | VM_SHARED;
 
 	return 0;
 }