MLK-11918-1 video: fbdev: mxc ipuv3 fb: Remove fbi NULL pointer check in ->remove()

MLK-11918-1 video: fbdev: mxc ipuv3 fb: Remove fbi NULL pointer check in ->remove()

The driver takes the pointer fbi as the driver data, so fbi cannot be a NULL
pointer in ->remove().  Let's remove the unnecessary NULL pointer check on
fbi.

This patch fixes the following issue reported by Coverity:
deref_ptr: Directly dereferencing pointer fbi.
	struct mxcfb_info *mxc_fbi = fbi->par;

Dereference before null check (REVERSE_INULL)
check_after_deref: Null-checking fbi suggests that it may be null, but it has
already been dereferenced on all paths leading to the check.
	if (!fbi)
		return 0;

Signed-off-by: Liu Ying <Ying.Liu@freescale.com>