autotools: Avoid find race for S = "${WORKDIR}"

For recipes with PACKAGES_remove = "${PN}", the find which removes .la files
can race against deletion of other directories in WORKDIR e.g.:

find: '/home/autobuilder/yocto-autobuilder/yocto-worker/nightly-oe-selftest/build/build/tmp/work/qemux86_64-poky-linux/init-ifupdown/1.0-r7/sstate-build-populate_lic': No such file or directory
| WARNING: /home/autobuilder/yocto-autobuilder/yocto-worker/nightly-oe-selftest/build/build/tmp/work/qemux86_64-poky-linux/init-ifupdown/1.0-r7/temp/run.do_configure.6558:1 exit 1 from
|   find /home/autobuilder/yocto-autobuilder/yocto-worker/nightly-oe-selftest/build/build/tmp/work/qemux86_64-poky-linux/init-ifupdown/1.0-r7 -name \*.la -delete

The simplest fix is to add the find option which ignores these kind of races.

[YOCTO #7522]

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>