RISC-V: KVM: make kvm_riscv_vcpu_fp_clean() static

There are no users outside vcpu_fp.c so make kvm_riscv_vcpu_fp_clean()
static.
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Signed-off-by: Anup Patel <anup.patel@wdc.com>

arch/riscv/kvm/vcpu_fp.c

@@ -26,7 +26,7 @@ void kvm_riscv_vcpu_fp_reset(struct kvm_vcpu *vcpu)
 		cntx->sstatus |= SR_FS_OFF;
 }
 
-void kvm_riscv_vcpu_fp_clean(struct kvm_cpu_context *cntx)
+static void kvm_riscv_vcpu_fp_clean(struct kvm_cpu_context *cntx)
 {
 	cntx->sstatus &= ~SR_FS;
 	cntx->sstatus |= SR_FS_CLEAN;