K 10
svn:author
V 3
mjg
K 8
svn:date
V 27
2017-10-13T20:31:56.546648Z
K 7
svn:log
V 231
mtx: change MTX_UNOWNED from 4 to 0

The value is spread all over the kernel and zeroing a register is
cheaper/shorter than setting it up to an arbitrary value.

Reduces amd64 GENERIC-NODEBUG .text size by 0.4%.

MFC after:	1 week

END