x86: uaccess_64: fix return value in __copy_from_user()

__copy_from_user() will return invalid value 16 when it fails to
access user space and the size is 10.

Signed-off-by: Hiroshi Shimamoto <[e-mail]>
Signed-off-by: Ingo Molnar <[e-mail]>

arch/x86/include/asm/uaccess_64.h

···
 		return ret;
 	case 10:
 		__get_user_asm(*(u64 *)dst, (u64 __user *)src,
-			       ret, "q", "", "=r", 16);
+			       ret, "q", "", "=r", 10);
 		if (unlikely(ret))
 			return ret;
 		__get_user_asm(*(u16 *)(8 + (char *)dst),