MIPS: sysmips: Remove duplicated include from syscall.c

Remove duplicated include.

Fixes: 7c0f6ba6 ("Replace <asm/uaccess.h> with <linux/uaccess.h> globally")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Markus Elfring <elfring@users.sourceforge.net>
Cc: Wei Yongjun <weiyongjun1@huawei.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/15213/


Signed-off-by: James Hogan <james.hogan@imgtec.com>