Merge from stable/10, r259742:

Merge from stable/10, r259742:

drm/ttm, drm/radeon: Replace EINTR/ERESTART by ERESTARTSYS...

... for msleep/cv_*wait() return values, where wait_event*() is used
on Linux. ERESTARTSYS is the return code expected by callers when the
operation was interrupted.

For instance, this is the case of radeon_cs_ioctl() (radeon_cs.c): if
an error occurs, and the code isn't ERESTARTSYS (eg. EINTR), it logs an
error.

Note that ERESTARTSYS is defined as ERESTART, but this keeps callers'
code close to Linux.

Submitted by:	avg@ (previous version)
Approved by:	re (gjb)

git-svn-id: svn://svn.freebsd.org/base/releng/10.0@259754 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f