sim:tests: Fix shodan_boot_test_robot to set gdb_port

To match the configurable GDB server port variable in shodan.resc
(The preset value should work :( Need to follow up with AntMicro)

Change-Id: Idd54376a111b7ac004ea542707d8e4f0ef77ebf0

shodan_boot.robot

diff --git a/shodan_boot.robot b/shodan_boot.robot
index e8c135c..f7595d6 100644
--- a/shodan_boot.robot
+++ b/shodan_boot.robot
@@ -19,6 +19,7 @@
 *** Keywords ***
 Prepare Machine
     Execute Command             path set ${ROOTDIR}
+    Execute Command             \$gdb_port = 3333
     Execute Script              ${SCRIPT}
     Execute Command             cpu0 IsHalted false
     Set Default Uart Timeout    300