rb532: Add support for kernel 4.4

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>

target/linux/rb532/patches-4.4/001-cmdline_hack.patch

@@ -0,0 +1,20 @@
+--- a/arch/mips/rb532/prom.c
++++ b/arch/mips/rb532/prom.c
+@@ -67,6 +67,7 @@ static inline unsigned long tag2ul(char
+ 	return simple_strtoul(num, 0, 10);
+ }
+ 
++extern char __image_cmdline[];
+ void __init prom_setup_cmdline(void)
+ {
+ 	static char cmd_line[COMMAND_LINE_SIZE] __initdata;
+@@ -108,6 +109,9 @@ void __init prom_setup_cmdline(void)
+ 	}
+ 	*(cp++) = ' ';
+ 
++	strcpy(cp,(__image_cmdline));
++	cp += strlen(__image_cmdline);
++
+ 	i = strlen(arcs_cmdline);
+ 	if (i > 0) {
+ 		*(cp++) = ' ';