SWUpdate: Added recipe for 2018.03

Signed-off-by: Stefano Babic <sbabic@denx.de>

recipes-support/swupdate/swupdate_2018.03.bb

@@ -0,0 +1,4 @@
+require swupdate.inc
+require swupdate_tools.inc
+
+SRCREV = "25a35039bc67905b636d871272a682e766a33165"