powerpc/32s: move hash code patching out of MMU_init_hw()

For KASAN, hash table handling will be activated early for
accessing to KASAN shadow areas.

In order to avoid any modification of the hash functions while
they are still used with the early hash table, the code patching
is moved out of MMU_init_hw() and put close to the big-bang switch
to the final hash table.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/mm/mmu_decl.h

@@ -130,6 +130,7 @@ extern void wii_memory_fixups(void);
  */
 #ifdef CONFIG_PPC32
 extern void MMU_init_hw(void);
+void MMU_init_hw_patch(void);
 unsigned long mmu_mapin_ram(unsigned long base, unsigned long top);
 #endif