common: Drop checkflash() and checkdram()

These functions are not used in U-Boot. Drop them.

Signed-off-by: Simon Glass <sjg@chromium.org>

include/common.h

@@ -63,8 +63,6 @@ void	hang		(void) __attribute__ ((noreturn));
 
 #include <display_options.h>
 
-int checkflash(void);
-int checkdram(void);
 extern u8 __dtb_dt_begin[];	/* embedded device tree blob */
 extern u8 __dtb_dt_spl_begin[];	/* embedded device tree blob for SPL/TPL */