/dev/mem: make reads and writes interruptible

In 8619e5bdee ("/dev/mem: Bail out upon SIGKILL."), /dev/mem became
killable, and that commit noted:

  Theoretically, reading/writing /dev/mem and /dev/kmem can become
  "interruptible". But this patch chose "killable". Future patch will
  make them "interruptible" so that we can revert to "killable" if
  some program regressed.

So now we take the next step in making it "interruptible", by changing
fatal_signal_pending() into signal_pending().

Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Link: https://lore.kernel.org/r/20220407122638.490660-1-Jason@zx2c4.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/char/mem.c

@@ -101,7 +101,7 @@ static inline bool should_stop_iteration(void)
 {
 	if (need_resched())
 		cond_resched();
-	return fatal_signal_pending(current);
+	return signal_pending(current);
 }
 
 /*