common: Move main_loop() to init.h

Move this function out of common.h and into a better place.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>

include/common.h

@@ -63,9 +63,6 @@ void	hang		(void) __attribute__ ((noreturn));
 
 #include <display_options.h>
 
-/* common/main.c */
-void	main_loop	(void);
-
 int checkflash(void);
 int checkdram(void);
 extern u8 __dtb_dt_begin[];	/* embedded device tree blob */