[PATCH] the rest of ->get_sb() switchover

[PATCH] the rest of ->get_sb() switchover

Switch over ext3, ufs, reiserfs, msdos, vfat, isofs, qnx4, hpfs, efs,
udf, romfs, bfs, affs, hfs, adfs, cramfs, ntfs, jffs, jffs2 and freevxfs
to new ->get_sb().

Kill ->read_super() that is thus no longer used.