mtd: add altera quadspi driver

Add Altera Generic Quad SPI Controller support. The controller
converts SPI NOR flash to parallel flash interface. So it is
not like other SPI flash, but rather like CFI flash.

Signed-off-by: Thomas Chou <thomas@wytron.com.tw>
diff --git a/drivers/mtd/Makefile b/drivers/mtd/Makefile
index c23c0c1..7f018a4 100644
--- a/drivers/mtd/Makefile
+++ b/drivers/mtd/Makefile
@@ -11,6 +11,7 @@
 obj-$(CONFIG_MTD) += mtd-uclass.o
 obj-$(CONFIG_MTD_PARTITIONS) += mtdpart.o
 obj-$(CONFIG_MTD_CONCAT) += mtdconcat.o
+obj-$(CONFIG_ALTERA_QSPI) += altera_qspi.o
 obj-$(CONFIG_HAS_DATAFLASH) += at45.o
 obj-$(CONFIG_FLASH_CFI_DRIVER) += cfi_flash.o
 obj-$(CONFIG_FLASH_CFI_MTD) += cfi_mtd.o