consolidate kernel-side struct sigaction declarations

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/arch/mips/include/asm/signal.h b/arch/mips/include/asm/signal.h
index cf4a080..197f636 100644
--- a/arch/mips/include/asm/signal.h
+++ b/arch/mips/include/asm/signal.h
@@ -21,4 +21,6 @@
 #include <asm/sigcontext.h>
 #include <asm/siginfo.h>
 
+#define __ARCH_HAS_ODD_SIGACTION
+
 #endif /* _ASM_SIGNAL_H */