automation: disable terminal echo in xilinx test scripts

The default terminal settings in Linux will enable echo which interferes with
these tests. Set the value in the script to avoid failure caused by a settings
reset.

Signed-off-by: Victor Lira <victorm.lira@amd.com>
Acked-by: Stefano Stabellini <sstabellini@kernel.org>
(cherry picked from commit 2f73ef4bd7)

automation/scripts/xilinx-smoke-dom0-x86_64.sh

@@ -124,7 +124,7 @@ sleep 5
 sh /scratch/gitlab-runner/${TEST_BOARD}.sh 1
 sleep 5
 set +e
-stty -F ${SERIAL_DEV} 57600
+stty -F ${SERIAL_DEV} 57600 -echo
 
 # Capture test result and power off board before exiting.
 export PASSED="${PASS_MSG}"

automation/scripts/xilinx-smoke-dom0less-arm64.sh

@@ -128,7 +128,7 @@ cd $START
 # connect to serial
 SERIAL_DEV="/dev/serial/zynq"
 set +e
-stty -F ${SERIAL_DEV} 115200
+stty -F ${SERIAL_DEV} 115200 -echo
 
 # Capture test result and power off board before exiting.
 export PASSED="${passed}"