Add OAISIM_UE_IMAGE default

Change-Id: I6e1d1451ba051dd34ac6d1d32c64e563dfdf1e42
diff --git a/Makefile b/Makefile
index 8a744f4..27d4499 100644
--- a/Makefile
+++ b/Makefile
@@ -27,6 +27,7 @@
 RKE2_K8S_VERSION  ?= v1.23.4+rke2r1
 K8S_VERSION       ?= v1.20.11
 
+OAISIM_UE_IMAGE ?= andybavier/lte-uesoftmodem:1.1.0-$(shell uname -r)
 ENABLE_ROUTER ?= true
 ENABLE_OAISIM ?= true
 ENABLE_GNBSIM ?= true