[media] SoC Camera: OMAP1: update for recent videobuf changes

Recent locking related videobuf changes has not been incorporated into the new
OMAP1 camera driver. Fix it.

Created and tested against linux-2.6.37-rc1.

Signed-off-by: Janusz Krzysztofik <jkrzyszt@tis.icnet.pl>
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>