riscv: qemu: Enable MTD NOR flash support

Enable support to the 2 NOR flashes on the QEMU RISC-V virt machine.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/board/emulation/qemu-riscv/Kconfig b/board/emulation/qemu-riscv/Kconfig
index 0818048..a7de82d 100644
--- a/board/emulation/qemu-riscv/Kconfig
+++ b/board/emulation/qemu-riscv/Kconfig
@@ -64,5 +64,7 @@
 	imply VIRTIO_PCI
 	imply VIRTIO_NET
 	imply VIRTIO_BLK
+	imply MTD_NOR_FLASH
+	imply CFI_FLASH
 
 endif