ALSA: hda - Missing NULL check in hda_beep.c

Added a NULL check of input_allocate_device() in hda_beep.c.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/hda/hda_beep.c b/sound/pci/hda/hda_beep.c
index b1796ae..3ecd7e7 100644
--- a/sound/pci/hda/hda_beep.c
+++ b/sound/pci/hda/hda_beep.c
@@ -88,6 +88,10 @@
 	snprintf(beep->phys, sizeof(beep->phys),
 		"card%d/codec#%d/beep0", codec->bus->card->number, codec->addr);
 	input_dev = input_allocate_device();
+	if (!input_dev) {
+		kfree(beep);
+		return -ENOMEM;
+	}
 
 	/* setup digital beep device */
 	input_dev->name = "HDA Digital PCBeep";