agp/intel: put back check that we have a driver for the bridge.

On my 945 laptop + radeon GPU, I was getting an oops on boot without this
check which seems to have gotten dropped in the rework.

Signed-off-by: Dave Airlie <airlied@redhat.com>
This commit is contained in:
Dave Airlie 2010-04-20 16:34:20 +10:00
commit 10fd883ce3