powerpc/mm: Move disable_radix handling into mmu_early_init_devtree()

Move the handling of the disable_radix command line argument into the
newly created mmu_early_init_devtree().

It's an MMU option so it's preferable to have it in an mm related file,
and it also means platforms that don't support radix don't have to carry
the code.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/kernel/prom.c

@@ -647,14 +647,6 @@ static void __init early_reserve_mem(void)
 #endif
 }
 
-static bool disable_radix;
-static int __init parse_disable_radix(char *p)
-{
-	disable_radix = true;
-	return 0;
-}
-early_param("disable_radix", parse_disable_radix);
-
 void __init early_init_devtree(void *params)
 {
 	phys_addr_t limit;
@@ -744,11 +736,6 @@ void __init early_init_devtree(void *params)
 	 */
 	spinning_secondaries = boot_cpu_count - 1;
 #endif
-	/*
-	 * now fixup radix MMU mode based on kernel command line
-	 */
-	if (disable_radix)
-		cur_cpu_spec->mmu_features &= ~MMU_FTR_RADIX;
 
 	mmu_early_init_devtree();
 

arch/powerpc/mm/init_64.c

@@ -413,7 +413,18 @@ EXPORT_SYMBOL_GPL(realmode_pfn_to_page);
 #endif /* CONFIG_SPARSEMEM_VMEMMAP/CONFIG_FLATMEM */
 
 #ifdef CONFIG_PPC_STD_MMU_64
+static bool disable_radix;
+static int __init parse_disable_radix(char *p)
+{
+	disable_radix = true;
+	return 0;
+}
+early_param("disable_radix", parse_disable_radix);
+
 void __init mmu_early_init_devtree(void)
 {
+	/* Disable radix mode based on kernel command line. */
+	if (disable_radix)
+		cur_cpu_spec->mmu_features &= ~MMU_FTR_RADIX;
 }
 #endif /* CONFIG_PPC_STD_MMU_64 */