cmd/mem.c, test/cmd/mem_copy.c: Add <compiler.h>

These files require <compiler.h> in order to have MEM_SUPPORT_64BIT_DATA
be defined but currently rely on a long indirect include path to get it.
Add this directly.

Signed-off-by: Tom Rini <trini@konsulko.com>
diff --git a/cmd/mem.c b/cmd/mem.c
index 9e71677..e5b9cb2 100644
--- a/cmd/mem.c
+++ b/cmd/mem.c
@@ -14,6 +14,7 @@
 #include <bootretry.h>
 #include <cli.h>
 #include <command.h>
+#include <compiler.h>
 #include <console.h>
 #include <display_options.h>
 #ifdef CONFIG_MTD_NOR_FLASH