riscv: Introduce configuration for 64bit version Microblaze V

The commit 7576ab2facae ("riscv: Add support for AMD/Xilinx MicroBlaze V")
added support for 32bit version. 64bit version is also available that's why
wire it up too.
DT is providing description for generic QEMU target.

Signed-off-by: Michal Simek <michal.simek@amd.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
diff --git a/arch/riscv/dts/Makefile b/arch/riscv/dts/Makefile
index bf32ead..de35658 100644
--- a/arch/riscv/dts/Makefile
+++ b/arch/riscv/dts/Makefile
@@ -10,6 +10,7 @@
 dtb-$(CONFIG_TARGET_STARFIVE_VISIONFIVE2) += jh7110-starfive-visionfive-2.dtb
 dtb-$(CONFIG_TARGET_TH1520_LPI4A) += th1520-lichee-pi-4a.dtb
 dtb-$(CONFIG_TARGET_XILINX_MBV) += xilinx-mbv32.dtb
+dtb-$(CONFIG_TARGET_XILINX_MBV) += xilinx-mbv64.dtb
 dtb-$(CONFIG_TARGET_ASPEED_AST2700_IBEX) += ast2700-ibex.dtb
 
 include $(srctree)/scripts/Makefile.dts