... 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)
a883f5eadb