mmc: renesas: Fix R-Car spelling

The correct spelling is R-Car, including the dash, update the usage.
Comment changes only, no functional change.

Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
diff --git a/drivers/mmc/renesas-sdhi.c b/drivers/mmc/renesas-sdhi.c
index 92afa6a..556f07e 100644
--- a/drivers/mmc/renesas-sdhi.c
+++ b/drivers/mmc/renesas-sdhi.c
@@ -571,7 +571,7 @@
 	int i, ret = 0, sret;
 	u32 caps, reg;
 
-	/* Only supported on Renesas RCar */
+	/* Only supported on Renesas R-Car */
 	if (!(priv->caps & TMIO_SD_CAP_RCAR_UHS))
 		return -EINVAL;