busybox: Add syslog-init alternative only if SysV in enabled

busybox: Add syslog-init alternative only if SysV in enabled

If systemd is enabled then syslog is handled through a service file
and related files in /etc/init.d are removed. This removes following
warning:

WARNING: busybox: NOT adding alternative provide /etc/init.d/syslog:
/etc/init.d/syslog.busybox does not exist

Signed-off-by: Muhammad Shakeel <muhammad_shakeel@mentor.com>
Signed-off-by: Saul Wold <sgw@linux.intel.com>