tf-cov-make: use 'main' branch for TF-M tests and extras repo

Switch to the 'main' branch for TF-M tests and the extras
repository, in response to the recent changes [1] in TF-A.

[1]: https://review.trustedfirmware.org/c/TF-A/trusted-firmware-a/+/26263

Signed-off-by: Manish V Badarkhe <Manish.Badarkhe@arm.com>
Change-Id: I0c75a712c570e70cc19d12f473d534777d7183d4
diff --git a/script/tf-coverity/tf-cov-make b/script/tf-coverity/tf-cov-make
index 1e6171f..c048532 100755
--- a/script/tf-coverity/tf-cov-make
+++ b/script/tf-coverity/tf-cov-make
@@ -38,7 +38,7 @@
 if [ ! -d "$TF_M_TESTS_DIR" ]; then
     git clone "$TF_M_TESTS_URL_REPO" "$TF_M_TESTS_DIR"
     cd "$TF_M_TESTS_DIR"
-    git checkout master
+    git checkout main
 fi
 
 cd "$TF_SOURCES"
@@ -46,7 +46,7 @@
 if [ ! -d "$TF_M_EXTRAS_DIR" ]; then
     git clone "$TF_M_EXTRAS_URL_REPO" "$TF_M_EXTRAS_DIR"
     cd "$TF_M_EXTRAS_DIR"
-    git checkout master
+    git checkout main
 fi
 
 cd "$TF_SOURCES"