Remove explanatory comments from includes

I noticed a comment by an include and remembered that I think these
don't really provide much value -- sometimes they are just editorial,
and sometimes they are obsolete.  I think it's better to just remove
them.  Tested by rebuilding.

Approved-By: Andrew Burgess <aburgess@redhat.com>

gdb/bsd-kvm.c

@@ -28,7 +28,7 @@
 #include "process-stratum-target.h"
 #include "value.h"
 #include "gdbcore.h"
-#include "inferior.h"          /* for get_exec_file */
+#include "inferior.h"
 #include "gdbthread.h"
 #include "gdbsupport/pathstuff.h"
 #include "gdbsupport/gdb_tilde_expand.h"