Documentation/features: Remove unicore32 from kcov and kmemleak

Documentation/features: Remove unicore32 from kcov and kmemleak

Commit 3839a7460721 ("Documentation/features: Add kcov") and
commit 4641961cff2f ("Documentation/features: Add kmemleak") were added
shortly after the unicore32 port was removed in commit fb37409a01b0
("arch: remove unicore32 port"). Remove the unicore32 feature lines from
kcov and kmemleak as well.

Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
Link: https://lore.kernel.org/r/20200707090922.4746-1-tklauser@distanz.ch
Signed-off-by: Jonathan Corbet <corbet@lwn.net>