mips: Add a reset_cpu() function

The current do_reset() is called from a command context. Add a function
which can be used from anywhere, as is done on ARM.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/mips/cpu/cpu.c b/arch/mips/cpu/cpu.c
index acfc9dc..4434650 100644
--- a/arch/mips/cpu/cpu.c
+++ b/arch/mips/cpu/cpu.c
@@ -4,6 +4,7 @@
  * Wolfgang Denk, DENX Software Engineering, <wd@denx.de>
  */
 
+#include <cpu_func.h>
 #include <command.h>
 #include <init.h>
 #include <linux/compiler.h>
@@ -20,9 +21,14 @@
 		/* NOP */;
 }
 
-int do_reset(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
+void reset_cpu(void)
 {
 	_machine_restart();
+}
+
+int do_reset(struct cmd_tbl *cmdtp, int flag, int argc, char *const argv[])
+{
+	reset_cpu();
 
 	return 0;
 }