Match list schema to run schema.
Fix a couple prototype warnings.
Separate structures and constants.
Make it possible to build cheritest in a list-only mode.

Enable list-only mode when built as a cross tool.
Build cheritest as a cross build tool when targeting mips64.
Add an option to embed the list of cheritest tests in the kernel.

The list is stored in a .cheri_cheritest_list section.  It can be
extracted with a suitable objcopy with the command:

objcopy -j .cheri_cheritest_list \
    --set-section-flags .cheri_cheritest_list=load -O binary \
    kernel outputfile
Embed the cheritest test list.
Fix warnings to allow build.