fb: push down the BKL in the ioctl handler

Framebuffer is heavily BKL dependant at the moment so just wrap the ioctl
handler in the driver as we push down.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Alan Cox <alan@redhat.com>
Cc: Krzysztof Helt <krzysztof.h1@poczta.fm>
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>