powerpc/32s: Move early_mmu_init() into mmu.c

early_mmu_init() is independent of MMU type and not
directly linked to tlb handling.

In a following patch, tlb.c will be restricted to HASH mmu.

Move early_mmu_init() into mmu.c which is common.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/e51b5e2fe6bca623b33116403043d3a1b5eaf826.1603348103.git.christophe.leroy@csgroup.eu

arch/powerpc/mm/book3s32/mmu.c

@@ -471,3 +471,7 @@ void __init setup_kuap(bool disabled)
 		pr_warn("KUAP cannot be disabled yet on 6xx when compiled in\n");
 }
 #endif
+
+void __init early_init_mmu(void)
+{
+}

arch/powerpc/mm/book3s32/tlb.c

@@ -104,7 +104,3 @@ void hash__flush_tlb_page(struct vm_area_struct *vma, unsigned long vmaddr)
 		flush_hash_pages(mm->context.id, vmaddr, pmd_val(*pmd), 1);
 }
 EXPORT_SYMBOL(hash__flush_tlb_page);
-
-void __init early_init_mmu(void)
-{
-}