rockchip: block: add rkmtd class and drivers

Add rkmtd class and drivers to create a virtual block device
to transfer Rockchip boot block data to and from NAND with
block orientated tools like "ums" and "rockusb".

Signed-off-by: Johan Jonker <jbx6244@gmail.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>
diff --git a/drivers/block/Makefile b/drivers/block/Makefile
index a161d14..fdcba5c 100644
--- a/drivers/block/Makefile
+++ b/drivers/block/Makefile
@@ -11,6 +11,7 @@
 
 ifndef CONFIG_SPL_BUILD
 obj-$(CONFIG_IDE) += ide.o
+obj-$(CONFIG_RKMTD) += rkmtd.o
 endif
 obj-$(CONFIG_SANDBOX) += sandbox.o host-uclass.o host_dev.o
 obj-$(CONFIG_$(SPL_TPL_)BLOCK_CACHE) += blkcache.o
@@ -19,3 +20,4 @@
 obj-$(CONFIG_EFI_MEDIA) += efi-media-uclass.o
 obj-$(CONFIG_EFI_MEDIA_SANDBOX) += sb_efi_media.o
 obj-$(CONFIG_EFI_MEDIA_BLK) += efi_blk.o
+