MIPS: Remove unneeded version.h includes from arch/mips/

It was pointed out by 'make versioncheck' that some includes of
linux/version.h are not needed in arch/mips/.
This patch removes them.

Signed-off-by: Jesper Juhl <jj@chaosbits.net>
To: LKML <linux-kernel@vger.kernel.org>
Cc: trivial@kernel.org
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2540/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>