Fix breakage in MIPS siginfo handling

MIPS's siginfo handling has been broken since this commit:

	commit 574c4866e33d648520a8bd5bf6f573ea6e554e88
	Author: Al Viro <viro@zeniv.linux.org.uk>
	Date:   Sun Nov 25 22:24:19 2012 -0500
	consolidate kernel-side struct sigaction declarations

for 64-bit BE MIPS CPUs.

The UAPI variant looks like this:

	struct sigaction {
		unsigned int	sa_flags;
		__sighandler_t	sa_handler;
		sigset_t	sa_mask;
	};

but the core kernel's variant looks like this:

	struct sigaction {
	#ifndef __ARCH_HAS_ODD_SIGACTION
		__sighandler_t	sa_handler;
		unsigned long	sa_flags;
	#else
		unsigned long	sa_flags;
		__sighandler_t	sa_handler;
	#endif
	#ifdef __ARCH_HAS_SA_RESTORER
		__sigrestore_t sa_restorer;
	#endif
		sigset_t	sa_mask;
	};

The problem is that sa_flags has been changed from an unsigned int to an
unsigned long.

Fix this by making sa_flags unsigned int if __ARCH_HAS_ODD_SIGACTION is
defined.

Whilst we're at it, rename __ARCH_HAS_ODD_SIGACTION to
__ARCH_HAS_IRIX_SIGACTION.

Signed-off-by: David Howells <dhowells@redhat.com>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org
Acked-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>