xfs: fix broken log reservation debugging

xlog_print_tic_res() is supposed to print a human readable string for
each element of the log ticket reservation array.  Unfortunately, I
forgot to update the string array when we added rmap & reflink support,
so the debug message prints "region[3]: (null) - 352 bytes" which isn't
useful at all.  Add the missing elements and add a build check so that
we don't forget again to add a string when adding a new XLOG_REG_TYPE.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>