m68k: atari core - Kill warn_unused_result warnings

warning: ignoring return value of 'request_irq', declared with attribute
warn_unused_result

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
diff --git a/arch/m68k/atari/atakeyb.c b/arch/m68k/atari/atakeyb.c
index f3c343b..a5f33c0 100644
--- a/arch/m68k/atari/atakeyb.c
+++ b/arch/m68k/atari/atakeyb.c
@@ -566,14 +566,19 @@
 
 int atari_keyb_init(void)
 {
+	int error;
+
 	if (atari_keyb_done)
 		return 0;
 
 	kb_state.state = KEYBOARD;
 	kb_state.len = 0;
 
-	request_irq(IRQ_MFP_ACIA, atari_keyboard_interrupt, IRQ_TYPE_SLOW,
-		    "keyboard/mouse/MIDI", atari_keyboard_interrupt);
+	error = request_irq(IRQ_MFP_ACIA, atari_keyboard_interrupt,
+			    IRQ_TYPE_SLOW, "keyboard/mouse/MIDI",
+			    atari_keyboard_interrupt);
+	if (error)
+		return error;
 
 	atari_turnoff_irq(IRQ_MFP_ACIA);
 	do {