GFS2: Log code fixes

This patch removes a log lock from around atomic operation where
it is not needed, removes an unused variable, and also changes
a void pointer used incorrectly to a struct page pointer.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

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

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