MIPS: Properly align the .data..init_task section.

Improper alignment can lead to unbootable systems and/or random
crashes.

[ralf@linux-mips.org: This is a lond standing bug since
6eb10bc9

 (kernel.org) rsp.
c422a10917f75fd19fa7fe070aaaa23e384dae6f (lmo) [MIPS: Clean up linker script
using new linker script macros.] so dates back to 2.6.32.]

Signed-off-by: David Daney <david.daney@cavium.com>
Cc: linux-mips@linux-mips.org
Cc: <stable@vger.kernel.org>
Patchwork: https://patchwork.linux-mips.org/patch/3881/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>