recipes: Start WORKDIR -> UNPACKDIR transition

Replace references of WORKDIR with UNPACKDIR where it makes sense to do
so in preparation for changing the default value of UNPACKDIR.

(From OE-Core rev: 1f18b9a512800860d5153d89eb82b56388efad6f)

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

meta/recipes-support/numactl/numactl_git.bb

@@ -52,7 +52,7 @@ do_install_ptest() {
         install -m 0755 ${B}/test/$i ${D}${PTEST_PATH}/test
     done
 
-    install -m 0755 ${WORKDIR}/Makefile ${D}${PTEST_PATH}/
+    install -m 0755 ${UNPACKDIR}/Makefile ${D}${PTEST_PATH}/
     install -m 0755 ${B}/.libs/numactl ${D}${PTEST_PATH}/
 }