arm64: switch to generic old sigaction() (compat-only)

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index 24dce47..1f27c58 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -210,6 +210,7 @@
 	select COMPAT_BINFMT_ELF
 	select HAVE_UID16
 	select OLD_SIGSUSPEND3
+	select COMPAT_OLD_SIGACTION
 	help
 	  This option enables support for a 32-bit EL0 running under a 64-bit
 	  kernel at EL1. AArch32-specific components such as system calls,