package/swupdate: note init script tokenizing limitation

Command line options reference:
https://sbabic.github.io/swupdate/_sources/swupdate.txt

Signed-off-by: Matthew Weber <matthew.weber@rockwellcollins.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

package/swupdate/swupdate.sh

@@ -5,6 +5,9 @@
 
 # Override these variables in sourced script(s) located
 # in /usr/lib/swupdate/conf.d or /etc/swupdate/conf.d
+# NOTE: There are substrings used in some swupdate commands which will
+#       need to be wrapped in a script to prevent tokenizing
+#       ( -p/-P post/pre cmds are good examples)
 SWUPDATE_ARGS="-v ${SWUPDATE_EXTRA_ARGS}"
 SWUPDATE_WEBSERVER_ARGS=""
 SWUPDATE_SURICATTA_ARGS=""