[XFS] Don't assert if trying to mount with blocksize > pagesize
If we don't do the blocksize/PAGESIZE check before calling
xfs_sb_validate_fsb_count() we can assert if we try to mount with a
blocksize > pagesize. The assert is valid so leave it and just move the
blocksize/pagesize check earlier.
SGI-PV: 983734
SGI-Modid: xfs-linux-melb:xfs-kern:31365a
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com> Signed-off-by: David Chinner <dgc@sgi.com>