KVM: selftests: Add check_steal_time_uapi() implementation for LoongArch

Define check_steal_time_uapi() for LoongArch so that the steal_time test
builds.  Note, while LoongArch's steal_time_init() has some funky asserts,
none of the code is uniquely verifying KVM's uAPI.

Cc: Jiakai Xu <xujiakai2025@iscas.ac.cn>
Cc: Jiakai Xu <jiakaiPeanut@gmail.com>
Cc: Andrew Jones <andrew.jones@oss.qualcomm.com>
Cc: Anup Patel <anup@brainfault.org>
Cc: Tianrui Zhao <zhaotianrui@loongson.cn>
Cc: Bibo Mao <maobibo@loongson.cn>
Cc: Huacai Chen <chenhuacai@kernel.org>
Fixes: 40351ed ("KVM: selftests: Refactor UAPI tests into dedicated function")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20260420192644.3892050-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Author: sean-jc

tools/testing/selftests/kvm/steal_time.c

@@ -461,6 +461,11 @@ static void steal_time_dump(struct kvm_vm *vm, uint32_t vcpu_idx)
 	ksft_print_msg("    version:   %d\n", st->version);
 	ksft_print_msg("    preempted: %d\n", st->preempted);
 }
+
+static void check_steal_time_uapi(void)
+{
+
+}
 #endif
 
 static void *do_steal_time(void *arg)