honor the bootloader's bootargs

Only overwrite the bootloader's bootargs if "chosen" exists in the dtb

Signed-off-by: Imre Kaloz <kaloz@openwrt.org>

SVN-Revision: 43802

target/linux/ramips/patches-3.14/0110-fix_bootargs_handling.patch

+--- a/arch/mips/ralink/of.c
++++ b/arch/mips/ralink/of.c
+@@ -3,7 +3,7 @@
+  * under the terms of the GNU General Public License version 2 as published
+  * by the Free Software Foundation.
+  *
+- * Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
++ * Copyright (C) 2008-2014 Imre Kaloz <kaloz@openwrt.org>
+  * Copyright (C) 2008-2009 Gabor Juhos <juhosg@openwrt.org>
+  * Copyright (C) 2013 John Crispin <blogic@openwrt.org>
+  */
+@@ -91,6 +91,17 @@ static int __init early_init_dt_find_mem
+ 	return 0;
+ }
+ 
++static int chosen_dtb;
++
++static int __init early_init_dt_find_chosen(unsigned long node, const char *uname,
++				     int depth, void *data)
++{
++	if (depth == 1 && !strcmp(uname, "chosen"))
++		chosen_dtb = 1;
++
++	return 0;
++}
++
+ extern struct boot_param_header __image_dtb;
+ 
+ void __init plat_mem_setup(void)
+@@ -103,7 +114,9 @@ void __init plat_mem_setup(void)
+ 	 */
+ 	__dt_setup_arch(&__image_dtb);
+ 
+-	strlcpy(arcs_cmdline, boot_command_line, COMMAND_LINE_SIZE);
++	of_scan_flat_dt(early_init_dt_find_chosen, NULL);
++	if (chosen_dtb)
++		strlcpy(arcs_cmdline, boot_command_line, COMMAND_LINE_SIZE);
+ 
+ 	of_scan_flat_dt(early_init_dt_find_memory, NULL);
+ 	if (memory_dtb)