lint-stable-003-whitespace: Exclude DTB files

This excludes Devicetree blob files from the list of files to check for
superfluous whitespaces. A DTB file has recently been added in commit
33079b8174 ("lib/device_tree: Add some FDT helper functions").

Change-Id: Ic25ee5361163446370c530cccefa3bf085895d15
Signed-off-by: Maximilian Brune <maximilian.brune@9elements.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/82638
Reviewed-by: Eric Lai <ericllai@google.com>
Reviewed-by: Lean Sheng Tan <sheng.tan@9elements.com>
Reviewed-by: Shuo Liu <shuo.liu@intel.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/util/lint/lint-stable-003-whitespace b/util/lint/lint-stable-003-whitespace
index b4e50f0..367369b 100755
--- a/util/lint/lint-stable-003-whitespace
+++ b/util/lint/lint-stable-003-whitespace
@@ -11,7 +11,7 @@
 # shellcheck source=helper_functions.sh
 . "${LINTDIR}/helper_functions.sh"
 
-EXCLUDELIST='^src/vendorcode/|^util/kconfig/|^util/nvidia/cbootimage|^util/goswid|__pycache__|COPYING|LICENSE|README|_shipped$|\.patch$|\.bin$|\.hex$|\.jpg$|\.gif$|\.ttf$|\.woff$|\.png$|\.eot$|\.vbt$|\.ico$|\.md$|\.apcb$'
+EXCLUDELIST='^src/vendorcode/|^util/kconfig/|^util/nvidia/cbootimage|^util/goswid|__pycache__|COPYING|LICENSE|README|_shipped$|\.patch$|\.bin$|\.hex$|\.jpg$|\.gif$|\.ttf$|\.woff$|\.png$|\.eot$|\.vbt$|\.ico$|\.md$|\.apcb$|\.dtb$'
 INCLUDELIST="src util payloads Makefile* toolchain.mk tests"
 
 # shellcheck disable=SC2086,SC2046