spi: renesas: Fix R-Car spelling

The correct spelling is R-Car, including the dash, update the usage.
Kconfig strings and comment changes only, no functional change.

Signed-off-by: Marek Vasut <marek.vasut+renesas@mailbox.org>
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index fd5cb36..96ea033 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -420,7 +420,7 @@
 	imply SPI_FLASH_SFDP_SUPPORT
 	help
 	  Enable the Renesas RPC SPI driver, used to access SPI NOR flash
-	  on Renesas RCar Gen3 SoCs. This uses driver model and requires a
+	  on Renesas R-Car Gen3 SoCs. This uses driver model and requires a
 	  device tree binding to operate.
 
 config ROCKCHIP_SFC