[MIPS] Use SYSVIPC_COMPAT to fix various problems on N32

N32 SysV IPC system calls should use 32-bit compatible code.
arch/mips/kernel/linux32.c have similar compatible code for O32, but
ipc/compat.c seems more complete.  We can use it for both N32 and O32.

This patch should fix these problems (and other possible problems):

http://www.linux-mips.org/cgi-bin/mesg.cgi?a=linux-mips&i=1149188824.6986.6.camel%40diimka-laptop
http://www.linux-mips.org/cgi-bin/mesg.cgi?a=linux-mips&i=44C6B829.8050508%40caviumnetworks.com

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig
index 27f83e6..2308c8e 100644
--- a/arch/mips/Kconfig
+++ b/arch/mips/Kconfig
@@ -1940,6 +1940,11 @@
 	depends on MIPS32_COMPAT
 	default y
 
+config SYSVIPC_COMPAT
+	bool
+	depends on COMPAT && SYSVIPC
+	default y
+
 config MIPS32_O32
 	bool "Kernel support for o32 binaries"
 	depends on MIPS32_COMPAT