Make the getmemsize() prototype available in memsizes.h, for code that

doesn't want to go to the hassle of processing a full memory map.

src/arch/i386/image/nbi.c

@@ -2,6 +2,7 @@
 #include <assert.h>
 #include <realmode.h>
 #include <gateA20.h>
+#include <memsizes.h>
 #include <gpxe/uaccess.h>
 #include <gpxe/segment.h>
 #include <gpxe/image.h>