mn10300: Select CONFIG_HAVE_UID16 to fix build failure

mn10300 builds fail with

fs/stat.c: In function 'cp_old_stat':
fs/stat.c:163:2: error: 'old_uid_t' undeclared

ipc/util.c: In function 'ipc64_perm_to_ipc_perm':
ipc/util.c:540:2: error: 'old_uid_t' undeclared

Select CONFIG_HAVE_UID16 and remove local definition of CONFIG_UID16
to fix the problem.

Fixes: fbc416ff ("arm64: fix building without CONFIG_UID16")
Cc: Arnd Bergmann <arnd@arndb.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

arch/mn10300/Kconfig

 config MN10300
 	def_bool y
 	select HAVE_OPROFILE
+	select HAVE_UID16
 	select GENERIC_IRQ_SHOW
 	select ARCH_WANT_IPC_PARSE_VERSION
 	select HAVE_ARCH_TRACEHOOK
@@ -37,9 +38,6 @@ config HIGHMEM
 config NUMA
 	def_bool n
 
-config UID16
-	def_bool y
-
 config RWSEM_GENERIC_SPINLOCK
 	def_bool y