hisilicon: add Hi3519DV500/Hi3516DV500 (V5 aarch64) firmware

The aarch64 Cortex-A55 (V5/HISI_OT) counterpart of hi3516cv6xx, as one
hi3519dv500 image with hi3516dv500 as an alias:

- hi3519dv500_ultimate_defconfig: aarch64 musl, linux 5.10 (openipc/linux
  branch hisilicon-hi3519dv500), arm64 Image + FIT, squashfs.
- board/hi3519dv500: kernel config, fit-image.its (DDR 0x40000000, arm64
  0x80000 text offset), post-image.sh, plus the repack wiring in Makefile.
- hisilicon-osdrv-hi3519dv500: load script + vendor MPP userspace .so from
  the Hi3519DV500 SDK V1.0.1.1.

Boots to a shell on the qemu-hisilicon hi3519dv500 machine (SMP + Ethernet).
majestic, divinus and hisilicon-opensdk have no aarch64 DV500 build yet and
are left off; source-built sensors will come from openhisilicon.

Author: widgetii

Makefile

@@ -101,6 +101,8 @@ endif
 repack:
 ifeq ($(BR2_OPENIPC_SOC_FAMILY),"hi3516cv6xx")
 	@$(call PREPARE_REPACK,firmware.bin,$(shell expr $(subst ",,$(BR2_OPENIPC_FLASH_SIZE)) \* 1024),,,nor)
+else ifeq ($(BR2_OPENIPC_SOC_FAMILY),"hi3519dv500")
+	@$(call PREPARE_REPACK,firmware.bin,$(shell expr $(subst ",,$(BR2_OPENIPC_FLASH_SIZE)) \* 1024),,,nor)
 else ifneq ($(wildcard $(TARGET)/images/firmware.bin),)
 	@$(call PREPARE_REPACK,firmware.bin,8192,,,nor)
 else

br-ext-chip-hisilicon/board/hi3519dv500/fit-image.its

@@ -0,0 +1,43 @@
+/dts-v1/;
+
+/*
+ * aarch64 FIT for Hi3519DV500/Hi3516DV500. DDR base 0x40000000; the kernel
+ * loads at the standard arm64 0x80000 text offset.
+ */
+
+/ {
+	description = "Linux Kernel";
+	#address-cells = <1>;
+
+	images {
+		fdt-1 {
+			description = "dtb";
+			data = /incbin/("fdt.dtb");
+			type = "flat_dt";
+			arch = "arm64";
+			compression = "none";
+			load = <0x40000000>;
+		};
+
+		linux_kernel {
+			description = "Linux";
+			data = /incbin/("Image");
+			type = "kernel";
+			arch = "arm64";
+			os = "Linux";
+			compression = "none";
+			load = <0x40080000>;
+			entry = <0x40080000>;
+		};
+	};
+
+	configurations {
+		default = "config-1";
+		config-1 {
+			description = "Linux";
+			kernel = "linux_kernel";
+			fdt = "fdt-1";
+			loadables = "linux_kernel", "fdt-1";
+		};
+	};
+};