libfdt: Introduce new ARCH_FIXUP_FDT option

Add new Kconfig option to disable arch_fixup_fdt() calls for cases where
U-Boot shouldn't update memory setup in DTB file.
One example of usage of this option is to boot OS with different memory
setup than U-Boot use.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/arm/lib/bootm-fdt.c b/arch/arm/lib/bootm-fdt.c
index 4481f9e..a517550 100644
--- a/arch/arm/lib/bootm-fdt.c
+++ b/arch/arm/lib/bootm-fdt.c
@@ -25,6 +25,7 @@
 
 DECLARE_GLOBAL_DATA_PTR;
 
+#ifdef CONFIG_ARCH_FIXUP_FDT
 int arch_fixup_fdt(void *blob)
 {
 	bd_t *bd = gd->bd;
@@ -60,3 +61,4 @@
 
 	return 0;
 }
+#endif
diff --git a/arch/arm/lib/bootm.c b/arch/arm/lib/bootm.c
index c20ef22..f9ed7fe 100644
--- a/arch/arm/lib/bootm.c
+++ b/arch/arm/lib/bootm.c
@@ -367,8 +367,10 @@
 	if (images->ft_addr) {
 		off = fdt_path_offset(images->ft_addr, "/memory");
 		if (off < 0) {
+#ifdef CONFIG_ARCH_FIXUP_FDT
 			if (arch_fixup_fdt(images->ft_addr))
 				puts("## WARNING: fixup memory failed!\n");
+#endif
 		}
 	}
 #endif
diff --git a/arch/mips/lib/bootm.c b/arch/mips/lib/bootm.c
index aa0475a..0c6a4ab 100644
--- a/arch/mips/lib/bootm.c
+++ b/arch/mips/lib/bootm.c
@@ -253,6 +253,7 @@
 #endif
 }
 
+#ifdef CONFIG_ARCH_FIXUP_FDT
 int arch_fixup_fdt(void *blob)
 {
 #if CONFIG_IS_ENABLED(MIPS_BOOT_FDT) && CONFIG_IS_ENABLED(OF_LIBFDT)
@@ -264,6 +265,7 @@
 	return 0;
 #endif
 }
+#endif
 
 static int boot_setup_fdt(bootm_headers_t *images)
 {