sh: Align .machvec.init section on a 4-byte boundary.

.machvec.init can be misaligned with the recent machvec changes,
forcibly align it on the boundary that it expects, as before.

Signed-off-by: Takashi YOSHII <takashi.yoshii.ze@hitachi.com>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>