powerpc/47x: Remove early_init_mmu_47x() to fix no previous prototype

4xx/iss476-smp_defconfig leads to:

  CC      arch/powerpc/mm/nohash/tlb.o
arch/powerpc/mm/nohash/tlb.c:322:13: error: no previous prototype for 'early_init_mmu_47x' [-Werror=missing-prototypes]
  322 | void __init early_init_mmu_47x(void)
      |             ^~~~~~~~~~~~~~~~~~

early_init_mmu_47x() is used only at one place and only locally.

Fold it into its only caller and remove it.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/0a667b7c2e05d3cf41ecd38f33cc334083a61c8d.1692282396.git.christophe.leroy@csgroup.eu

arch/powerpc/mm/nohash/tlb.c

@@ -318,17 +318,6 @@ EXPORT_SYMBOL(flush_tlb_page);
 
 #endif /* CONFIG_SMP */
 
-#ifdef CONFIG_PPC_47x
-void __init early_init_mmu_47x(void)
-{
-#ifdef CONFIG_SMP
-	unsigned long root = of_get_flat_dt_root();
-	if (of_get_flat_dt_prop(root, "cooperative-partition", NULL))
-		mmu_clear_feature(MMU_FTR_USE_TLBIVAX_BCAST);
-#endif /* CONFIG_SMP */
-}
-#endif /* CONFIG_PPC_47x */
-
 /*
  * Flush kernel TLB entries in the given range
  */
@@ -746,8 +735,10 @@ void setup_initial_memory_limit(phys_addr_t first_memblock_base,
 #else /* ! CONFIG_PPC64 */
 void __init early_init_mmu(void)
 {
-#ifdef CONFIG_PPC_47x
-	early_init_mmu_47x();
-#endif
+	unsigned long root = of_get_flat_dt_root();
+
+	if (IS_ENABLED(CONFIG_PPC_47x) && IS_ENABLED(CONFIG_SMP) &&
+	    of_get_flat_dt_prop(root, "cooperative-partition", NULL))
+		mmu_clear_feature(MMU_FTR_USE_TLBIVAX_BCAST);
 }
 #endif /* CONFIG_PPC64 */