xfs: kill off xfs_printk()

xfs_alert_tag() can be defined using xfs_alert(), and thereby avoid
using xfs_printk() altogether.  This is the only remaining use of
xfs_printk(), so changing it this way means xfs_printk() can simply
be eliminated.can simply be eliminated.can simply be eliminated.can
simply be eliminated.can simply be eliminated.can simply be
eliminated.can simply be eliminated.can simply be eliminated.can
simply be eliminated.

Also add format checking to the non-debug inline function xfs_debug.
Miscellaneous function prototype argument alignment.

(Updated to delete the definition of xfs_printk(), which is
no longer used or needed.)

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Alex Elder <aelder@sgi.com>