i.MX31: fix framebuffer locking regressions

Recent framebuffer locking patches first made affected systems unbootable,
then the dead-lock has been fixed but as of 2.6.31-rc4 the framebuffer on
mx3 machines doesn't work. Fix this.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
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>