swupdate: use sysconfdir variable

Signed-off-by: Diego Rondini <diego.rondini@kynetics.com>

recipes-support/swupdate/swupdate.inc

@@ -21,7 +21,7 @@ PACKAGES =+ "${PN}-www"
 FILES_${PN}-www = "/www/*"
 FILES_${PN}-dev = "${includedir}"
 FILES_${PN}-staticdev = "${libdir}"
-FILES_${PN} = "${bindir}/* /etc"
+FILES_${PN} = "${bindir}/* ${sysconfdir}"
 
 S = "${WORKDIR}/git/"