MIPS: 64-bit: Fix o32 lookup_dcookie syscall

An o32 aplication passes a 64-bit value in a pair of registers; a 64-bit
kernel expects a 64-bit argument in a single register.

Signed-off-by: Chen Jie <chenj@lemote.com>
Signed-off-by: Hu Hongbing <huhb@lemote.com>
Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/kernel/linux32.c b/arch/mips/kernel/linux32.c
index 6242bc6..b77fefa 100644
--- a/arch/mips/kernel/linux32.c
+++ b/arch/mips/kernel/linux32.c
@@ -428,3 +428,9 @@
 	return do_fork(clone_flags, newsp, &regs, 0,
 	               parent_tidptr, child_tidptr);
 }
+
+asmlinkage long sys32_lookup_dcookie(u32 a0, u32 a1, char __user *buf,
+	size_t len)
+{
+	return sys_lookup_dcookie(merge_64(a0, a1), buf, len);
+}