configs/qemu_arm_vexpress_tz_defconfig: bump tf-a and u-boot versions

- Bump TF-A LTS 2.12
- Bump u-boot to version 2026.04.

smhload command has been removed from u-boot 2022.07 [1], use
"load hostfs" generic command as suggested by the documentation [2].

This commit adds BR2_TARGET_UBOOT_NEEDS_DTC=y, because the new
2026.04 version does need dtc. Adding host-dtc also avoid uboot build
failures on hosts with libyaml (uboot builds its own dtc if none is
defined in DTC build variable).

This commit also removes BR2_TOOLCHAIN_BUILDROOT_CXX=y, which was
forgotten when the defconfig was switched to Bootlin toolchain, in
commit [3].

[1] dcc4f9623e
[2] https://docs.u-boot-project.org/en/latest/usage/semihosting.html#migrating-from-smhload
[3] dbe0896826

Signed-off-by: Romain Naour <romain.naour@smile.fr>
[Julien:
 - add BR2_TARGET_UBOOT_NEEDS_DTC=y
 - remove BR2_TOOLCHAIN_BUILDROOT_CXX=y
]
Signed-off-by: Julien Olivain <ju.o@free.fr>

board/qemu/arm-vexpress-tz/u-boot.config

@@ -1,5 +1,5 @@
 CONFIG_SYS_TEXT_BASE=0x60000000
-CONFIG_BOOTCOMMAND="smhload zImage ${kernel_addr_r} && smhload rootfs.cpio.uboot ${ramdisk_addr_r} && setenv bootargs console=ttyAMA0,115200 earlyprintk=serial,ttyAMA0,115200 && bootz ${kernel_addr_r} ${ramdisk_addr_r} ${fdt_addr}"
+CONFIG_BOOTCOMMAND="load hostfs - ${kernel_addr_r} zImage && load hostfs - ${ramdisk_addr_r} rootfs.cpio.uboot  && setenv bootargs console=ttyAMA0,115200 earlyprintk=serial,ttyAMA0,115200 && bootz ${kernel_addr_r} ${ramdisk_addr_r} ${fdt_addr}"
 CONFIG_SEMIHOSTING=y
 # Drop flash accesses
 CONFIG_ENV_IS_IN_FLASH=n

board/qemu/patches/uboot/uboot.hash

@@ -1,3 +1,3 @@
 # Locally calculated
-sha256  68e065413926778e276ec3abd28bb32fa82abaa4a6898d570c1f48fbdb08bcd0  u-boot-2022.04.tar.bz2
 sha256  b99611f1ed237bf3541bdc8434b68c96a6e05967061f992443cb30aabebef5b3  u-boot-2024.01.tar.bz2
+sha256  ac7c04b8b7004923b00a4e5d6699c5df4d21233bac9fda690d8cfbc209fff2fd  u-boot-2026.04.tar.bz2