ALSA: es18xx: Remove the unneeded result variable

Return the value inb() directly instead of storing it in another redundant
 variable.
Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: ye xingchen <ye.xingchen@zte.com.cn>
Link: https://lore.kernel.org/r/20220920064605.215318-1-ye.xingchen@zte.com.cnSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/isa/es18xx.c

@@ -1344,11 +1344,8 @@ ES18XX_SINGLE("GPO1 Switch", 0, ES18XX_PM, 1, 1, ES18XX_FL_PMPORT),
 
 static int snd_es18xx_config_read(struct snd_es18xx *chip, unsigned char reg)
 {
-	int data;
-
 	outb(reg, chip->ctrl_port);
-	data = inb(chip->ctrl_port + 1);
-	return data;
+	return inb(chip->ctrl_port + 1);
 }
 
 static void snd_es18xx_config_write(struct snd_es18xx *chip,