rsyslog: remove non-existent enable/disable systemd options

The configuration flags `--enable-systemd` and `--disable-systemd` do
not exist in rsyslog (and may have never existed; most likely copy-paste
from other packages which have said options); removing the options.

Signed-off-by: James Knight <james.knight@rockwellcollins.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/rsyslog/rsyslog.mk

@@ -66,11 +66,8 @@ endif
 
 ifeq ($(BR2_INIT_SYSTEMD),y)
 RSYSLOG_CONF_OPTS += \
-	--enable-systemd \
 	--with-systemdsystemunitdir=/usr/lib/systemd/system
 RSYSLOG_DEPENDENCIES += systemd
-else
-RSYSLOG_CONF_OPTS += --disable-systemd
 endif
 
 define RSYSLOG_INSTALL_INIT_SYSV