xbf(4): tsleep(9) -> tsleep_nsec(9)

[Scott Cheloha]

Given the SCSI_NOSLEEP split here I think the simplest thing we can do
is ask to sleep as much as we delay(9).

The question is: if you *could* poll in 10us intervals here with
tsleep_nsec(9), would you want to?  If so, then this works.  If
not, what is a more appropriate interval?

Index: pv/xbf.c
===================================================================
RCS file: /cvs/src/sys/dev/pv/xbf.c,v
retrieving revision 1.32
diff -u -p -r1.32 xbf.c
--- pv/xbf.c    17 Jul 2017 10:30:03 -0000      1.32
+++ pv/xbf.c    15 Jan 2020 06:20:25 -0000
@@ -738,7 +738,7 @@ xbf_poll_cmd(struct scsi_xfer *xs)
                if (ISSET(xs->flags, SCSI_NOSLEEP))
                        delay(10);
                else
-                       tsleep(xs, PRIBIO, "xbfpoll", 1);
+                       tsleep_nsec(xs, PRIBIO, "xbfpoll", USEC_TO_NSEC(10));
                xbf_intr(xs->sc_link->adapter_softc);
        } while(--timo > 0);