Mark temporary PSA crypto sim Perl scripts as executable

Signed-off-by: Tom Cosgrove <tom.cosgrove@arm.com>
diff --git a/tests/psa-client-server/psasim/src/psa_sim_generate.pl b/tests/psa-client-server/psasim/src/psa_sim_generate.pl
old mode 100644
new mode 100755
diff --git a/tests/psa-client-server/psasim/src/psa_sim_serialise.pl b/tests/psa-client-server/psasim/src/psa_sim_serialise.pl
old mode 100644
new mode 100755