buildroot

libarchive: add hash and enable lzma support

Add libarchive hash. Enable lzma support.
Both xz and lzma support are provided by the xz library.

[Thomas: explicitly pass --with-lzma when xz is available.]

Signed-off-by: Nimai Mahajan <nimaim@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>