Remove unnecessary use of export

Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/tests/scripts/quiet/cmake b/tests/scripts/quiet/cmake
index c03d8c3..a34365b 100755
--- a/tests/scripts/quiet/cmake
+++ b/tests/scripts/quiet/cmake
@@ -12,8 +12,8 @@
 # export VERBOSE_LOGS=1
 
 # don't silence invocations containing these arguments
-export NO_SILENCE=" --version "
+NO_SILENCE=" --version "
 
-export TOOL="cmake"
+TOOL="cmake"
 
 . "$(dirname "$0")/quiet.sh"