arch/arm: add the Cortex-A720 core

This commit adds the Cortex-A720 core, which is a armv9.2a ISA.
See: [1] [2].

This CPU support was added in GCC 14. See [3] [4].

Cortex-A720 processors are included in boards such as the
Radxa Orion O6. See [5].

This CPU supports Aarch64 only at all exception levels (EL0 to EL3).

[1] https://developer.arm.com/Processors/Cortex-A720
[2] https://developer.arm.com/documentation/102530/0002/The-Cortex-A720--core/Cortex-A720--core-features
[3] https://gcc.gnu.org/gcc-14/changes.html#aarch64
[4] https://gcc.gnu.org/git/?p=gcc.git;a=blob;f=gcc/config/aarch64/aarch64-cores.def;hb=releases/gcc-14.1.0#l180
[5] https://radxa.com/products/orion/o6/

Signed-off-by: Julien Olivain <ju.o@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

arch/Config.in.arm

@@ -518,6 +518,14 @@ config BR2_neoverse_n2
 	select BR2_ARM_CPU_HAS_FP_ARMV8
 	select BR2_ARM_CPU_ARMV9A
 	select BR2_ARCH_NEEDS_GCC_AT_LEAST_11
+
+comment "armv9.2a cores"
+config BR2_cortex_a720
+	bool "Cortex-A720 (aka hunter)"
+	depends on BR2_ARCH_IS_64
+	select BR2_ARM_CPU_HAS_FP_ARMV8
+	select BR2_ARM_CPU_ARMV9A
+	select BR2_ARCH_NEEDS_GCC_AT_LEAST_14
 endchoice
 
 config BR2_ARM_ENABLE_NEON
@@ -914,6 +922,8 @@ config BR2_GCC_TARGET_CPU
 	# armv9.0a
 	default "cortex-a710"	if BR2_cortex_a710
 	default "neoverse-n2"	if BR2_neoverse_n2
+	# armv9.2a
+	default "cortex-a720"	if BR2_cortex_a720
 
 config BR2_GCC_TARGET_ABI
 	default "aapcs-linux"	if BR2_arm || BR2_armeb