KVM: arm64: selftests: Test for setting ID register from usersapce

Add tests to verify setting ID registers from userspace is handled
correctly by KVM. Also add a test case to use ioctl
KVM_ARM_GET_REG_WRITABLE_MASKS to get writable masks.

Signed-off-by: Jing Zhang <jingzhangos@google.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20231011195740.3349631-6-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

Author: jingzhangos

tools/testing/selftests/kvm/Makefile

@@ -156,6 +156,7 @@ TEST_GEN_PROGS_aarch64 += aarch64/debug-exceptions
 TEST_GEN_PROGS_aarch64 += aarch64/hypercalls
 TEST_GEN_PROGS_aarch64 += aarch64/page_fault_test
 TEST_GEN_PROGS_aarch64 += aarch64/psci_test
+TEST_GEN_PROGS_aarch64 += aarch64/set_id_regs
 TEST_GEN_PROGS_aarch64 += aarch64/smccc_filter
 TEST_GEN_PROGS_aarch64 += aarch64/vcpu_width_config
 TEST_GEN_PROGS_aarch64 += aarch64/vgic_init