libxlog: don't require a libxfs_xinit structure for xlog_init

libxlog: don't require a libxfs_xinit structure for xlog_init

xlog_init currently requires a libxfs_args structure to be passed in,
and then clobbers various log-related arguments to it.  There is no
good reason for that as all the required information can be calculated
without it.

Remove the x argument to xlog_init and xlog_is_dirty and the now unused
logBBstart member in struct libxfs_xinit.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Carlos Maiolino <cem@kernel.org>