powerpc/mm: Do hash device tree scanning earlier

Currently MMU initialisation (early_init_mmu()) consists of a mixture of
scanning the device tree, setting MMU feature bits, and then also doing
actual initialisation of MMU data structures.

We'd like to decouple the setting of the MMU features from the actual
setup. So split out the device tree scanning, and associated code, and
call it from mmu_init_early_devtree().

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
diff --git a/arch/powerpc/mm/init_64.c b/arch/powerpc/mm/init_64.c
index 0d51e6e..d023333 100644
--- a/arch/powerpc/mm/init_64.c
+++ b/arch/powerpc/mm/init_64.c
@@ -426,5 +426,8 @@
 	/* Disable radix mode based on kernel command line. */
 	if (disable_radix)
 		cur_cpu_spec->mmu_features &= ~MMU_FTR_RADIX;
+
+	if (!radix_enabled())
+		hash__early_init_devtree();
 }
 #endif /* CONFIG_PPC_STD_MMU_64 */