tcf-agent: Move to the latest master version

There has not been a release since 2018, the 1.7.0 release.  A number of
recent improvements around thumb and clang debugging prompted this move
to a newer version.

The patch is no longer necessary as it was a backport patch.

Signed-off-by: Mark Hatle <mark.hatle@kernel.crashing.org>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>