ALSA: hda/ca0132 - Fix superfluous unsigned check

Fix a warning by smatch,
 sound/pci/hda/patch_ca0132.c:714 dspio_send() warn: always true
 condition '(res >= 0) => (0-u32max >= 0)'

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/hda/patch_ca0132.c

@@ -1054,7 +1054,7 @@ static void chipio_enable_clocks(struct hda_codec *codec)
 static int dspio_send(struct hda_codec *codec, unsigned int reg,
 		      unsigned int data)
 {
-	unsigned int res;
+	int res;
 	int retry = 50;
 
 	/* send bits of data specified by reg to dsp */