cbfstool: add ppc64 support

cbfstool: add ppc64 support

The constant for ppc64 is 'hotstuff'. For many reasons.

Note that line 2894 of elf.h is not indented. This is because in the
original the line begins with a space. Checkpatch rejects that.
Checkpatch also rejects changing the space to a tab because that makes
it more than 80 chars. I rejected breaking the line because it makes it
even less readable. All the changes forced by checkpatch make the code
less readable.

Herman Hollerith would be proud.

Change-Id: I21f049fe8c655a30f17dff694b8f42789ad9efb7
Signed-off-by: Ronald G. Minnich <rminnich@gmail.com>
Reviewed-on: https://review.coreboot.org/12711
Reviewed-by: Timothy Pearson <tpearson@raptorengineeringinc.com>
Tested-by: build bot (Jenkins)