efifb: fix framebuffer handoff

Commit 4410f391 ("fbdev: add support for
handoff from firmware to hw framebuffers") didn't add fb_destroy
operation to efifb.  Fix it and change aperture_size to match size
passed to request_mem_region.

Addresses http://bugzilla.kernel.org/show_bug.cgi?id=15151



Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com>
Reported-by: Alex Zhavnerchik <alex.vizor@gmail.com>
Tested-by: Alex Zhavnerchik <alex.vizor@gmail.com>
Acked-by: Peter Jones <pjones@redhat.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Dave Airlie <airlied@redhat.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>