spi: mtk_qspi: add qspi driver for MT7629 SoC

This patch adds MT7629 qspi driver for accessing SPI NOR flash.

Signed-off-by: Guochun Mao <guochun.mao@mediatek.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Jagan Teki <jagan@openedev.com>
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 6085788..4a8a38b 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -132,6 +132,13 @@
 	  the SPI NOR flash on platforms embedding this Ralink / MediaTek
 	  SPI core, like MT7621/7628/7688.
 
+config MTK_QSPI
+	bool "Mediatek QSPI driver"
+	help
+	  Enable the Mediatek QSPI driver. This driver can be
+	  used to access the SPI NOR flash on platforms embedding this
+	  Mediatek QSPI IP core.
+
 config MVEBU_A3700_SPI
 	bool "Marvell Armada 3700 SPI driver"
 	select CLK_ARMADA_3720