We already depend on glib which has sha1, so we don't really need
openssl just for sha1.

The opensll dependency was added in commit caea9c5b
("igt/gem_userptr: Check read-only mappings").

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>