smccc: kvm_guest: Align with DISCOVER_IMPL_CPUS ABI

The ABI of the hypercall requires that R2 and R3 are 0. Explicitly pass
0 for these parameters.

Cc: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Fixes: 86edf6b ("smccc/kvm_guest: Enable errata based on implementation CPUs")
Reviewed-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
Link: https://lore.kernel.org/r/20250327163613.2516073-1-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

drivers/firmware/smccc/kvm_guest.c

@@ -95,7 +95,7 @@ void  __init kvm_arm_target_impl_cpu_init(void)
 
 	for (i = 0; i < max_cpus; i++) {
 		arm_smccc_1_1_invoke(ARM_SMCCC_VENDOR_HYP_KVM_DISCOVER_IMPL_CPUS_FUNC_ID,
-				     i, &res);
+				     i, 0, 0, &res);
 		if (res.a0 != SMCCC_RET_SUCCESS) {
 			pr_warn("Discovering target implementation CPUs failed\n");
 			goto mem_free;