xfs: print name of function causing fs shutdown instead of hex pointer

In xfs_do_force_shutdown, print the symbolic name of the function that
called us to shut down the filesystem instead of a raw hex pointer.
This makes debugging a lot easier:

XFS (sda): xfs_do_force_shutdown(0x2) called from line 2440 of file
	fs/xfs/xfs_log.c. Return address = ffffffffa038bc38

becomes:

XFS (sda): xfs_do_force_shutdown(0x2) called from line 2440 of file
	fs/xfs/xfs_log.c. Return address = xfs_trans_mod_sb+0x25

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>