package/x11r7/xdriver_xf86-video-siliconmotion: remove autoreconf

xdriver_xf86-video-siliconmotion no longer use the git repository.

commit: b343bc69

Signed-off-by: Romain Naour <romain.naour@openwide.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>