Previously, the grep command would detect the /usr/bin/share string
inside of the .ci/grep.sh file, so only check the device folder to
avoid this. Other folders shouldn't contain any kernels anyway.
[ci:skip-build]: Everything but linux-postmarketos-qcom-sm7150
built fine in CI, and linux-postmarketos-qcom-sm7150 built fine
locally. Building linux-postmarketos-qcom-sm7150 via the CI failed
because it took over 3 hours so the CI timed out.