rlink: fix speed table generation

The speed table generation (by using explicit
make -f Makefile.rlink) was broken since
865efd828a267992db0f2a92a731c5ce23a34236 Dec 2 2009 which did a bunch of
renaming and included hand-editing of a generated rlink_speed_table.c file.

This patch is compile-tested, i.e. the new generated rlink_speed_table.c
links fine with the rlink driver.

Change-Id: I1789a2f2f5bf20183b772d55c55fe68a0bd05cf5
Signed-off-by: Paul Fertser <fercerpav@gmail.com>
Reviewed-on: http://openocd.zylin.com/1431
Tested-by: jenkins
Reviewed-by: Spencer Oliver <spen@spen-soft.co.uk>