package/pmake: remove

Packaging pmake was required when we used the upstream libedit.
Since we have switched to using the autotools-based libedit,
pmake is no longer needed.

Because pmake is quite ugly, let's just drop it.

Signed-off-by: "Yann E. MORIN" <yann.morin.1998@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>