uapi: Use __kernel_long_t in struct msgbuf

x32 msgsnd/msgrcv system calls are the same as x86-64 msgsnd/msgrcv system
calls, which use 64-bit integer for long in struct msgbuf . But x32 long
is 32 bit.  This patch replaces long in struct msgbuf with __kernel_long_t.

Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
Link: http://lkml.kernel.org/r/1388182464-28428-5-git-send-email-hjl.tools@gmail.com
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

diff --cc include/uapi/linux/msg.h
Simple merge