Restore inadvertently deleted gba multiboot linkscript flag (fix #10)

Author: fincs

gba_mb.specs

@@ -1,7 +1,7 @@
 %include <sync-none.specs>
 
 *link:
-+ --gc-sections --no-warn-rwx-segments
++ -T gba_mb.ld%s --gc-sections --no-warn-rwx-segments
 
 *startfile:
 gba_crt0%O%s crti%O%s crtbegin%O%s