tests: install_rust: Also install clippy

clippy is used as part our tests, so it's useful to have it installed
while we're already installing rust.

In case of developers, they also better be using it. :-)

Fixes: #7974 -- part 0

Signed-off-by: Fabiano Fidêncio <fabiano.fidencio@intel.com>
(cherry picked from commit e125775863)

tests/install_rust.sh

@@ -42,3 +42,4 @@ else
 	$([ "$(whoami)" != "root" ] && echo sudo) ln -sf /usr/bin/g++ /bin/musl-g++
 fi
 rustup component add rustfmt
+rustup component add clippy