mtd: spi-nor-core: Allow using Micron mt35xu512aba in Octal DTR mode

Since this flash doesn't have a Profile 1.0 table, the Octal DTR
capabilities are enabled in the post SFDP fixup, along with the 8D-8D-8D
fast read settings.

Enable Octal DTR mode with 20 dummy cycles to allow running at the
maximum supported frequency of 200Mhz.

Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
diff --git a/drivers/mtd/spi/Kconfig b/drivers/mtd/spi/Kconfig
index 98c0b23..1b2ef37 100644
--- a/drivers/mtd/spi/Kconfig
+++ b/drivers/mtd/spi/Kconfig
@@ -180,6 +180,14 @@
 	help
 	  Add support for various STMicro SPI flash chips (M25Pxxx and N25Qxxx)
 
+config SPI_FLASH_MT35XU
+	bool "Micron MT35XU chip support"
+	depends on SPI_FLASH_STMICRO
+	help
+	 Add support for the Micron MT35XU chip. This is a separate config
+	 because the fixup hooks for this flash add extra size overhead. Boards
+	 that don't use the flash can disable this to save space.
+
 config SPI_FLASH_SST
 	bool "SST SPI flash support"
 	help