RISC-V: KVM: use EBUSY when !vcpu->arch.ran_atleast_once

vcpu_set_reg_config() and vcpu_set_reg_isa_ext() is throwing an
EOPNOTSUPP error when !vcpu->arch.ran_atleast_once. In similar cases
we're throwing an EBUSY error, like in mvendorid/marchid/mimpid
set_reg().

EOPNOTSUPP has a conotation of finality. EBUSY is more adequate in this
case since its a condition/error related to the vcpu lifecycle.

Change these EOPNOTSUPP instances to EBUSY.
Suggested-by: Andrew Jones <ajones@ventanamicro.com>
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

@@ -212,7 +212,7 @@ static int kvm_riscv_vcpu_set_reg_config(struct kvm_vcpu *vcpu,
 			vcpu->arch.isa[0] = reg_val;
 			kvm_riscv_vcpu_fp_reset(vcpu);
 		} else {
-			return -EOPNOTSUPP;
+			return -EBUSY;
 		}
 		break;
 	case KVM_REG_RISCV_CONFIG_REG(zicbom_block_size):
@@ -484,7 +484,7 @@ static int riscv_vcpu_set_isa_ext_single(struct kvm_vcpu *vcpu,
 			return -EINVAL;
 		kvm_riscv_vcpu_fp_reset(vcpu);
 	} else {
-		return -EOPNOTSUPP;
+		return -EBUSY;
 	}
 
 	return 0;