audit: Add CONFIG_HAVE_ARCH_AUDITSYSCALL

Currently AUDITSYSCALL has a long list of architecture depencency:
       depends on AUDIT && (X86 || PARISC || PPC || S390 || IA64 || UML ||
		SPARC64 || SUPERH || (ARM && AEABI && !OABI_COMPAT) || ALPHA)
The purpose of this patch is to replace it with HAVE_ARCH_AUDITSYSCALL
for simplicity.

Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
Acked-by: Will Deacon <will.deacon@arm.com> (arm)
Acked-by: Richard Guy Briggs <rgb@redhat.com> (audit)
Acked-by: Matt Turner <mattst88@gmail.com> (alpha)
Acked-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Signed-off-by: Eric Paris <eparis@redhat.com>
diff --git a/arch/alpha/Kconfig b/arch/alpha/Kconfig
index f23ab8b..437ef0d 100644
--- a/arch/alpha/Kconfig
+++ b/arch/alpha/Kconfig
@@ -21,6 +21,7 @@
 	select GENERIC_SMP_IDLE_THREAD
 	select GENERIC_STRNCPY_FROM_USER
 	select GENERIC_STRNLEN_USER
+	select HAVE_ARCH_AUDITSYSCALL
 	select HAVE_MOD_ARCH_SPECIFIC
 	select MODULES_USE_ELF_RELA
 	select ODD_RT_SIGACTION