spi: Migrate CONFIG_SH_QSPI to Kconfig

Signed-off-by: Tuomas Tynkkynen <tuomas@tuxera.com>
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 3d2cd2d..a1f9373 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -245,6 +245,12 @@
 	  Enable the SuperH SPI controller driver. This driver can be used
 	  on various SuperH SoCs, such as SH7757.
 
+config SH_QSPI
+	bool "Renesas Quad SPI driver"
+	help
+	  Enable the Renesas Quad SPI controller driver. This driver can be
+	  used on Renesas SoCs.
+
 config TI_QSPI
 	bool "TI QSPI driver"
 	help