GFS2: Use fs_<level> more often

Convert a couple of uses of pr_<level> to fs_<level>
Add and use fs_emerg.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

diff --cc fs/gfs2/quota.c
Simple merge

diff --cc fs/gfs2/util.c
Simple merge

diff --cc fs/gfs2/util.h
Simple merge