openssl: convert to Makefile.autotools.in and bump version to 0.9.8g

This patch converts building of OpenSSL to use Makefile.autotools.in and bumps
the version to 0.9.8g. The patches are updated to reflect this version upgrade.

A kconfig option for adding the OpenSSL engines is also added.

Signed-off-by: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com>