configs/hifive_unleashed: Update to use OpenSBI 1.2

Since the rest of RISC-V boards have been switched to use OpenSBI
1.2, let's update hifive_unleashed to use OpenSBI 1.2 too.

Resolves: https://bugs.busybox.net/show_bug.cgi?id=15658
Signed-off-by: Bin Meng <bmeng@tinylab.org>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>

configs/hifive_unleashed_defconfig

@@ -38,7 +38,7 @@ BR2_LINUX_KERNEL_INSTALL_TARGET=y
 # Bootloader
 BR2_TARGET_OPENSBI=y
 BR2_TARGET_OPENSBI_CUSTOM_VERSION=y
-BR2_TARGET_OPENSBI_CUSTOM_VERSION_VALUE="0.9"
+BR2_TARGET_OPENSBI_CUSTOM_VERSION_VALUE="1.2"
 BR2_TARGET_OPENSBI_PLAT="generic"
 BR2_TARGET_UBOOT=y
 BR2_TARGET_UBOOT_CUSTOM_VERSION=y