KVM: PPC: Book3S: Fix symbol undeclared warnings

Build the kernel with `C=2`:
arch/powerpc/kvm/book3s_hv_nested.c:572:25: warning: symbol
'kvmhv_alloc_nested' was not declared. Should it be static?
arch/powerpc/kvm/book3s_64_mmu_radix.c:350:6: warning: symbol
'kvmppc_radix_set_pte_at' was not declared. Should it be static?
arch/powerpc/kvm/book3s_hv.c:3568:5: warning: symbol
'kvmhv_p9_guest_entry' was not declared. Should it be static?
arch/powerpc/kvm/book3s_hv_rm_xics.c:767:15: warning: symbol 'eoi_rc'
was not declared. Should it be static?
arch/powerpc/kvm/book3s_64_vio_hv.c:240:13: warning: symbol
'iommu_tce_kill_rm' was not declared. Should it be static?
arch/powerpc/kvm/book3s_64_vio.c:492:6: warning: symbol
'kvmppc_tce_iommu_do_map' was not declared. Should it be static?
arch/powerpc/kvm/book3s_pr.c:572:6: warning: symbol 'kvmppc_set_pvr_pr'
was not declared. Should it be static?

Those symbols are used only in the files that define them so make them
static to fix the warnings.

Signed-off-by: Wang Wensheng <[e-mail]>
Signed-off-by: Paul Mackerras <[e-mail]>

arch/powerpc/kvm/book3s_64_mmu_radix.c

···
 	return __radix_pte_update(ptep, clr, set);
 }
 
-void kvmppc_radix_set_pte_at(struct kvm *kvm, unsigned long addr,
+static void kvmppc_radix_set_pte_at(struct kvm *kvm, unsigned long addr,
 			     pte_t *ptep, pte_t pte)
 {
 	radix__set_pte_at(kvm->mm, addr, ptep, pte, 0);

arch/powerpc/kvm/book3s_64_vio.c

···
 	return ret;
 }
 
-long kvmppc_tce_iommu_do_map(struct kvm *kvm, struct iommu_table *tbl,
+static long kvmppc_tce_iommu_do_map(struct kvm *kvm, struct iommu_table *tbl,
 		unsigned long entry, unsigned long ua,
 		enum dma_data_direction dir)
 {

arch/powerpc/kvm/book3s_64_vio_hv.c

···
 	return ret;
 }
 
-extern void iommu_tce_kill_rm(struct iommu_table *tbl,
+static void iommu_tce_kill_rm(struct iommu_table *tbl,
 		unsigned long entry, unsigned long pages)
 {
 	if (tbl->it_ops->tce_kill)

arch/powerpc/kvm/book3s_hv.c

···
  * Virtual-mode guest entry for POWER9 and later when the host and
  * guest are both using the radix MMU.  The LPIDR has already been set.
  */
-int kvmhv_p9_guest_entry(struct kvm_vcpu *vcpu, u64 time_limit,
+static int kvmhv_p9_guest_entry(struct kvm_vcpu *vcpu, u64 time_limit,
 			 unsigned long lpcr)
 {
 	struct kvmppc_vcore *vc = vcpu->arch.vcore;

arch/powerpc/kvm/book3s_hv_nested.c

···
 	kvmhv_set_nested_ptbl(gp);
 }
 
-struct kvm_nested_guest *kvmhv_alloc_nested(struct kvm *kvm, unsigned int lpid)
+static struct kvm_nested_guest *kvmhv_alloc_nested(struct kvm *kvm, unsigned int lpid)
 {
 	struct kvm_nested_guest *gp;
 	long shadow_lpid;

arch/powerpc/kvm/book3s_hv_rm_xics.c

···
 	return ics_rm_eoi(vcpu, irq);
 }
 
-unsigned long eoi_rc;
+static unsigned long eoi_rc;
 
 static void icp_eoi(struct irq_chip *c, u32 hwirq, __be32 xirr, bool *again)
 {

arch/powerpc/kvm/book3s_pr.c

···
 #endif
 }
 
-void kvmppc_set_pvr_pr(struct kvm_vcpu *vcpu, u32 pvr)
+static void kvmppc_set_pvr_pr(struct kvm_vcpu *vcpu, u32 pvr)
 {
 	u32 host_pvr;