util/lint: provide option to skip newline check

The newline lint check takes forever as it checks every file
in the git repo -- not just the files changed. To add insult to
injury these checks are performed on every commit. Allow one to
skip this check by setting the LINT_SKIP_NEWLINE_CHECK environment
variable.

Change-Id: I1cd5c50627b73d68b0da2fcb2d9546eb874a7959
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/20903
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>

util/lint/lint-stable-015-final-newlines

@@ -46,6 +46,10 @@ test_for_final_newline() {
 	done
 }
 
+if [ -n "${LINT_SKIP_NEWLINE_CHECK}" ]; then
+	exit 0
+fi
+
 ${FIND_FILES} | sed 's|^\./||' | sort | \
 	grep -v "$EXCLUDED_DIRS" | \
 	grep -v "$EXCLUDED_FILES" | \