drm/radeon/kms/atom: bump atom loop timeout from 1 sec to 5 secs

Some tables have delays that can cause the timeout to hit
even when not intended.

Should fix:
https://bugs.freedesktop.org/show_bug.cgi?id=27744


and related bugs.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>