arch: msgbuf.h: make uapi asm/msgbuf.h self-contained

Userspace cannot compile <asm/msgbuf.h> due to some missing type
definitions. For example, building it for x86 fails as follows:

CC usr/include/asm/msgbuf.h.s
In file included from usr/include/asm/msgbuf.h:6:0,
from <command-line>:32:
usr/include/asm-generic/msgbuf.h:25:20: error: field `msg_perm' has incomplete type
struct ipc64_perm msg_perm;
^~~~~~~~
usr/include/asm-generic/msgbuf.h:27:2: error: unknown type name `__kernel_time_t'
__kernel_time_t msg_stime; /* last msgsnd time */
^~~~~~~~~~~~~~~
usr/include/asm-generic/msgbuf.h:28:2: error: unknown type name `__kernel_time_t'
__kernel_time_t msg_rtime; /* last msgrcv time */
^~~~~~~~~~~~~~~
usr/include/asm-generic/msgbuf.h:29:2: error: unknown type name `__kernel_time_t'
__kernel_time_t msg_ctime; /* last change time */
^~~~~~~~~~~~~~~
usr/include/asm-generic/msgbuf.h:41:2: error: unknown type name `__kernel_pid_t'
__kernel_pid_t msg_lspid; /* pid of last msgsnd */
^~~~~~~~~~~~~~
usr/include/asm-generic/msgbuf.h:42:2: error: unknown type name `__kernel_pid_t'
__kernel_pid_t msg_lrpid; /* last receive pid */
^~~~~~~~~~~~~~

It is just a matter of missing include directive.

Include <asm/ipcbuf.h> to make it self-contained, and add it to
the compile-test coverage.

Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Masahiro Yamada <[e-mail]>
Cc: Arnd Bergmann <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

arch/mips/include/uapi/asm/msgbuf.h

···
 #ifndef _ASM_MSGBUF_H
 #define _ASM_MSGBUF_H
 
+#include <asm/ipcbuf.h>
 
 /*
  * The msqid64_ds structure for the MIPS architecture.

arch/parisc/include/uapi/asm/msgbuf.h

···
 #define _PARISC_MSGBUF_H
 
 #include <asm/bitsperlong.h>
+#include <asm/ipcbuf.h>
 
 /* 
  * The msqid64_ds structure for parisc architecture, copied from sparc.

arch/powerpc/include/uapi/asm/msgbuf.h

···
 #ifndef _ASM_POWERPC_MSGBUF_H
 #define _ASM_POWERPC_MSGBUF_H
 
+#include <asm/ipcbuf.h>
+
 /*
  * The msqid64_ds structure for the PowerPC architecture.
  * Note extra padding because this structure is passed back and forth

arch/sparc/include/uapi/asm/msgbuf.h

···
 #ifndef _SPARC_MSGBUF_H
 #define _SPARC_MSGBUF_H
 
+#include <asm/ipcbuf.h>
+
 /*
  * The msqid64_ds structure for sparc64 architecture.
  * Note extra padding because this structure is passed back and forth

arch/x86/include/uapi/asm/msgbuf.h

···
 #if !defined(__x86_64__) || !defined(__ILP32__)
 #include <asm-generic/msgbuf.h>
 #else
+
+#include <asm/ipcbuf.h>
+
 /*
  * The msqid64_ds structure for x86 architecture with x32 ABI.
  *

arch/xtensa/include/uapi/asm/msgbuf.h

···
 #ifndef _XTENSA_MSGBUF_H
 #define _XTENSA_MSGBUF_H
 
+#include <asm/ipcbuf.h>
+
 struct msqid64_ds {
 	struct ipc64_perm msg_perm;
 #ifdef __XTENSA_EB__

include/uapi/asm-generic/msgbuf.h

···
 #define __ASM_GENERIC_MSGBUF_H
 
 #include <asm/bitsperlong.h>
+#include <asm/ipcbuf.h>
+
 /*
  * generic msqid64_ds structure.
  *

usr/include/Makefile

···
 # Please consider to fix the header first.
 #
 # Sorted alphabetically.
-header-test- += asm/msgbuf.h
 header-test- += asm/sembuf.h
 header-test- += asm/shmbuf.h
 header-test- += asm/signal.h