Revert "posix-cpu-timers: Force next expiration recalc after itimer reset"

This reverts commit c322a963d522e9a4273e18c9d7bd6fd40a25160f which is
commit 406dd42bd1ba0c01babf9cde169bb319e52f6147 upstream.

It is reported to cause regressions.  A proposed fix has been posted,
but it is not in a released kernel yet.  So just revert this from the
stable release so that the bug is fixed.  If it's really needed we can
add it back in in a future release.

Link: https://lore.kernel.org/r/87ilz1pwaq.fsf@wylie.me.uk
Reported-by: "Alan J. Wylie" <alan@wylie.me.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Frederic Weisbecker <frederic@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

kernel/time/posix-cpu-timers.c

@@ -1201,6 +1201,8 @@ void set_process_cpu_timer(struct task_struct *tsk, unsigned int clkid,
 			}
 		}
 
+		if (!*newval)
+			return;
 		*newval += now;
 	}