RISC-V: KVM: use ENOENT in *_one_reg() when extension is unavailable

Following a similar logic as the previous patch let's minimize the EINVAL
usage in *_one_reg() APIs by using ENOENT when an extension that
implements the reg is not available.

For consistency we're also replacing an EOPNOTSUPP instance that should
be an ENOENT since it's an "extension is not available" error.
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Signed-off-by: Anup Patel <anup@brainfault.org>

arch/riscv/kvm/vcpu_onereg.c

@@ -135,12 +135,12 @@ static int kvm_riscv_vcpu_get_reg_config(struct kvm_vcpu *vcpu,
 		break;
 	case KVM_REG_RISCV_CONFIG_REG(zicbom_block_size):
 		if (!riscv_isa_extension_available(vcpu->arch.isa, ZICBOM))
-			return -EINVAL;
+			return -ENOENT;
 		reg_val = riscv_cbom_block_size;
 		break;
 	case KVM_REG_RISCV_CONFIG_REG(zicboz_block_size):
 		if (!riscv_isa_extension_available(vcpu->arch.isa, ZICBOZ))
-			return -EINVAL;
+			return -ENOENT;
 		reg_val = riscv_cboz_block_size;
 		break;
 	case KVM_REG_RISCV_CONFIG_REG(mvendorid):
@@ -459,7 +459,7 @@ static int riscv_vcpu_set_isa_ext_single(struct kvm_vcpu *vcpu,
 
 	host_isa_ext = kvm_isa_ext_arr[reg_num];
 	if (!__riscv_isa_extension_available(NULL, host_isa_ext))
-		return	-EOPNOTSUPP;
+		return -ENOENT;
 
 	if (!vcpu->arch.ran_atleast_once) {
 		/*