pinctrl: mediatek: Initialize variable *buf to zero

Coverity spotted that *buf is not initialized to zero in
mtk_pctrl_dbg_show. Using uninitialized variable *buf as argument to %s
when calling seq_printf. Fix this coverity by initializing *buf as zero.

Fixes: 184d8e13 ("pinctrl: mediatek: Add support for pin configuration dump via debugfs.")
Signed-off-by: Guodong Liu <Guodong.Liu@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20230118062036.26258-3-Guodong.Liu@mediatek.comSigned-off-by: Linus Walleij <linus.walleij@linaro.org>

drivers/pinctrl/mediatek/pinctrl-paris.c

@@ -717,7 +717,7 @@ static void mtk_pctrl_dbg_show(struct pinctrl_dev *pctldev, struct seq_file *s,
 			  unsigned int gpio)
 {
 	struct mtk_pinctrl *hw = pinctrl_dev_get_drvdata(pctldev);
-	char buf[PIN_DBG_BUF_SZ];
+	char buf[PIN_DBG_BUF_SZ] = { 0 };
 
 	(void)mtk_pctrl_show_one_pin(hw, gpio, buf, PIN_DBG_BUF_SZ);