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 <h-shimamoto@ct.jp.nec.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/include/asm/uaccess_64.h

@@ -46,7 +46,7 @@ int __copy_from_user(void *dst, const void __user *src, unsigned size)
 		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),