misc: integrate cbc_attach service

cbc_attach is one SOS service that enable IOC CBC line discipline feature.
It started by systemd by default, and exit if failed to set the line
discipline that means the platform does not support IOC.

Signed-off-by: Vineetha G Jaya Kumaran <vineetha.g.jaya.kumaran@intel.com>
Signed-off-by: Yuan Liu <yuan1.liu@intel.com>
Signed-off-by: Yu Wang <yu1.wang@intel.com>
Reviewed-by: Vineetha G Jaya Kumaran <vineetha.g.jaya.kumaran@intel.com>
Reviewed-by: Key Seong Lim <key.seong.lim@intel.com>
Reviewed-by: Alex Du <alek.du@intel.com>
Acked-by: Eddie Dong <eddie.dong@intel.com>

misc/cbc_attach/cbc_attach.service

@@ -0,0 +1,13 @@
+[Unit]
+Description=cbc attach
+DefaultDependencies=no
+After=sysinit.target local.target
+Before=basic.target
+
+[Service]
+ExecStart=/usr/bin/cbc_attach -f /dev/ttyS2
+Restart=always
+Type=notify
+
+[Install]
+WantedBy=basic.target