Two fresh LORs from the latest 11-stable

[Maxim Sobolev]

Seen those on our build box right after pulling latest update.

lock order reversal:
 1st 0xfffffe00f62564c0 bufwait (bufwait) @
/usr/home/sobomax/freebsd11.git/sys/kern/vfs_bio.c:3512
 2nd 0xfffff80003d33800 dirhash (dirhash) @
/usr/home/sobomax/freebsd11.git/sys/ufs/ufs/ufs_dirhash.c:281
stack backtrace:
#0 0xffffffff80ab5fc0 at witness_debugger+0x70
#1 0xffffffff80ab5eb4 at witness_checkorder+0xe54
#2 0xffffffff80a5f1d2 at _sx_xlock+0x72
#3 0xffffffff80d1d8dd at ufsdirhash_add+0x3d
#4 0xffffffff80d206aa at ufs_direnter+0x4da
#5 0xffffffff80d28d09 at ufs_mkdir+0x8a9
#6 0xffffffff810235e0 at VOP_MKDIR_APV+0xe0
#7 0xffffffff80b23ef8 at kern_mkdirat+0x208
#8 0xffffffff80ec7b2b at amd64_syscall+0x2db
#9 0xffffffff80ea767b at Xfast_syscall+0xfb

lock order reversal:
 1st 0xfffff80064d86d50 ufs (ufs) @
/usr/home/sobomax/freebsd11.git/sys/kern/vfs_subr.c:2523
 2nd 0xfffffe00f669fe00 bufwait (bufwait) @
/usr/home/sobomax/freebsd11.git/sys/ufs/ffs/ffs_vnops.c:263
 3rd 0xfffff800a5c4eb78 ufs (ufs) @
/usr/home/sobomax/freebsd11.git/sys/kern/vfs_subr.c:2523
stack backtrace:
#0 0xffffffff80ab5fc0 at witness_debugger+0x70
#1 0xffffffff80ab5eb4 at witness_checkorder+0xe54
#2 0xffffffff80a2f052 at __lockmgr_args+0x4c2
#3 0xffffffff80d18546 at ffs_lock+0xa6
#4 0xffffffff81023fd0 at VOP_LOCK1_APV+0xe0
#5 0xffffffff80b26aaa at _vn_lock+0x9a
#6 0xffffffff80b16ed4 at vget+0x64
#7 0xffffffff80b095cc at vfs_hash_get+0xcc
#8 0xffffffff80d14250 at ffs_vgetf+0x40
#9 0xffffffff80d0b4a6 at softdep_sync_buf+0x496
#10 0xffffffff80d19136 at ffs_syncvnode+0x256
#11 0xffffffff80cefed3 at ffs_truncate+0x8d3
#12 0xffffffff80d20851 at ufs_direnter+0x681
#13 0xffffffff80d28d09 at ufs_mkdir+0x8a9
#14 0xffffffff810235e0 at VOP_MKDIR_APV+0xe0
#15 0xffffffff80b23ef8 at kern_mkdirat+0x208
#16 0xffffffff80ec7b2b at amd64_syscall+0x2db
#17 0xffffffff80ea767b at Xfast_syscall+0xfb

-Max