K 10
svn:author
V 7
oshogbo
K 8
svn:date
V 27
2019-06-05T22:29:05.114185Z
K 7
svn:log
V 353
dtrace: 64-bits registers support

The registers in ilumos and FreeBSD have a different number.
In the illumos, last 32-bits register defined is SS an in FreeBSD is GS.
This off-by-one caused the uregs array to returns the wrong 64-bits register
on amd64.

Reviewed by:	markj
MFC after:	2 weeks
Differential Revision:	https://reviews.freebsd.org/D20363

END