devtools: ignore JSON files for SPDX check

The JSON file format does not support comments so there is no good
way to add SPDX license identifier.  This solves false positives
that arrive from the use of JSON in crypto dev tests.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>

devtools/check-spdx-tag.sh

@@ -25,8 +25,8 @@ check_spdx() {
 	':^*/Kbuild' ':^*/README' \
 	':^license/' ':^config/' ':^buildtools/' \
 	':^*.cocci' ':^*.abignore' \
-	':^*.map' ':^*.ini' ':^*.data' ':^*.cfg' ':^*.txt' \
-	':^*.svg' ':^*.png'\
+	':^*.map' ':^*.ini' ':^*.data' ':^*.json' ':^*.cfg' ':^*.txt' \
+	':^*.svg' ':^*.png' \
 	> $tmpfile
 
     errors=$(wc -l < $tmpfile)