cbmem: remove cbmem_set_top()

Now that the users of cbmem_set_top() always provide a consistent
cbmem_top() value there's no need to have cbmem_set_top() around.
Therefore, delete it.

Change-Id: I0c96e2b8b829eddbeb1fdf755ed59c51ea689d1b
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: http://review.coreboot.org/10314
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
Tested-by: build bot (Jenkins)
Reviewed-by: Kyösti Mälkki <kyosti.malkki@gmail.com>

src/arch/x86/boot/cbmem.c

@@ -40,7 +40,6 @@ void set_top_of_ram(uint64_t ramtop)
 {
 	backup_top_of_ram(ramtop);
 	ramtop_pointer = (void *)(uintptr_t)ramtop;
-	cbmem_set_top(ramtop_pointer);
 }
 
 static inline void *saved_ramtop(void)