powerpc: Remove extern from function implementations

Sparse reports several function implementations annotated with extern.
This is clearly incorrect, likely just copied from an actual extern
declaration in another file.

Fix the sparse warnings by removing extern.
Signed-off-by: Benjamin Gray <bgray@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231011053711.93427-6-bgray@linux.ibm.com

arch/powerpc/kernel/iommu.c

@@ -1074,10 +1074,10 @@ int iommu_tce_check_gpa(unsigned long page_shift, unsigned long gpa)
 }
 EXPORT_SYMBOL_GPL(iommu_tce_check_gpa);
 
-extern long iommu_tce_xchg_no_kill(struct mm_struct *mm,
-		struct iommu_table *tbl,
-		unsigned long entry, unsigned long *hpa,
-		enum dma_data_direction *direction)
+long iommu_tce_xchg_no_kill(struct mm_struct *mm,
+			    struct iommu_table *tbl,
+			    unsigned long entry, unsigned long *hpa,
+			    enum dma_data_direction *direction)
 {
 	long ret;
 	unsigned long size = 0;

arch/powerpc/kernel/traps.c

@@ -157,7 +157,7 @@ static int die_owner = -1;
 static unsigned int die_nest_count;
 static int die_counter;
 
-extern void panic_flush_kmsg_start(void)
+void panic_flush_kmsg_start(void)
 {
 	/*
 	 * These are mostly taken from kernel/panic.c, but tries to do
@@ -170,7 +170,7 @@ extern void panic_flush_kmsg_start(void)
 	bust_spinlocks(1);
 }
 
-extern void panic_flush_kmsg_end(void)
+void panic_flush_kmsg_end(void)
 {
 	kmsg_dump(KMSG_DUMP_PANIC);
 	bust_spinlocks(0);

arch/powerpc/kvm/book3s_64_vio.c

@@ -77,8 +77,8 @@ static void kvm_spapr_tce_liobn_put(struct kref *kref)
 	call_rcu(&stit->rcu, kvm_spapr_tce_iommu_table_free);
 }
 
-extern void kvm_spapr_tce_release_iommu_group(struct kvm *kvm,
-		struct iommu_group *grp)
+void kvm_spapr_tce_release_iommu_group(struct kvm *kvm,
+				       struct iommu_group *grp)
 {
 	int i;
 	struct kvmppc_spapr_tce_table *stt;
@@ -105,8 +105,8 @@ extern void kvm_spapr_tce_release_iommu_group(struct kvm *kvm,
 	rcu_read_unlock();
 }
 
-extern long kvm_spapr_tce_attach_iommu_group(struct kvm *kvm, int tablefd,
-		struct iommu_group *grp)
+long kvm_spapr_tce_attach_iommu_group(struct kvm *kvm, int tablefd,
+				      struct iommu_group *grp)
 {
 	struct kvmppc_spapr_tce_table *stt = NULL;
 	bool found = false;