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/powerpc/Kconfig b/arch/powerpc/Kconfig
index b44b52c..96627d6 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -139,6 +139,7 @@
 	select OLD_SIGACTION if PPC32
 	select HAVE_DEBUG_STACKOVERFLOW
 	select HAVE_IRQ_EXIT_ON_IRQ_STACK
+	select HAVE_ARCH_AUDITSYSCALL
 
 config GENERIC_CSUM
 	def_bool CPU_LITTLE_ENDIAN