mmc: matsushita-common: Handle bus width 0

Handle bus width 0 as 1-bit bus to assure valid content of
MATSU_SD_OPTION register WIDTH field.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Jaehoon Chung <jh80.chung@samsung.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>

drivers/mmc/matsushita-common.c

@@ -504,6 +504,7 @@ static int matsu_sd_set_bus_width(struct matsu_sd_priv *priv,
 	u32 val, tmp;
 
 	switch (mmc->bus_width) {
+	case 0:
 	case 1:
 		val = MATSU_SD_OPTION_WIDTH_1;
 		break;