um: Fix IPC on um

commit c1d7e01d (ipc: use Kconfig options for __ARCH_WANT_[COMPAT_]IPC_PARSE_VERSION)
forgot UML and broke IPC on it.
Also UML has to select ARCH_WANT_IPC_PARSE_VERSION usin Kconfig.

Reported-and-tested-by: <Toralf Förster toralf.foerster@gmx.de>
Signed-off-by: NRichard Weinberger <richard@nod.at>

arch/x86/um/Kconfig

@@ -21,6 +21,7 @@ config 64BIT
 config X86_32
 	def_bool !64BIT
 	select HAVE_AOUT
+	select ARCH_WANT_IPC_PARSE_VERSION
 
 config X86_64
 	def_bool 64BIT