The uefi-mm logs are printed over the soc uart1 port and a log file name
is assigned to it when the model is launched. So do not override that file
name for automated tests with -j parameter.

Change-Id: I69e24cc5e148c7ea0ebe29a4a0a661fb4a24fa1f
Signed-off-by: Thomas Abraham <thomas.abraham@arm.com>