pw_poller: print "Sleep" and amount of seconds on the same line

Maybe to others it is obvious that these two lines are related:

** Sleep
119.694849

But to me it wasn't.

New format:

** Sleep 119.694849 seconds

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>

Author: vladimiroltean

pw_poller.py

@@ -300,7 +300,7 @@ def run(self, life) -> None:
 
                 secs = 120 - (datetime.datetime.now() - req_time).total_seconds()
                 if secs > 0:
-                    log("Sleep", secs)
+                    log(f"Sleep {secs} seconds")
                 log_end_sec()
         except KeyboardInterrupt:
             pass  # finally will still run, but don't splat