boards: intel_s1000_crb: fix xt-gdb cannot find register error

With the new RI-2018.0 XCC, xt-gdb complains about not being able
to find register f0. Turns out that xt-gdb needs to be told which
file to look at (the file command) before a load command can be
issued. So swap these two commands in the load_elf.txt file.

Signed-off-by: Daniel Leung <daniel.leung@intel.com>