powerpc/mm: Fix section mismatch warning in early_check_vec5()

early_check_vec5() is called from and calls __init routines, so should
also be __init.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/mm/init_64.c

@@ -381,7 +381,7 @@ early_param("disable_radix", parse_disable_radix);
  * /chosen/ibm,architecture-vec-5 to see if the hypervisor is willing to do
  * radix.  If not, we clear the radix feature bit so we fall back to hash.
  */
-static void early_check_vec5(void)
+static void __init early_check_vec5(void)
 {
 	unsigned long root, chosen;
 	int size;