fix memtest86plus download/build

the mkdir command in update/project/repo, added for
pico-pi integration, broke a bunch of other downloads.

the fix is a bit of a hack but it should hold for now.

Signed-off-by: Leah Rowe <leah@libreboot.org>

script/update/project/repo

@@ -84,7 +84,8 @@ clone_project()
 	[ ! -d "${location}" ] || \
 		rm -Rf "${location}" || \
 		    fail "clone_project: Can't remove directory '${location}'"
-	mkdir -p ${location%/*}
+	[ "${name}" != "rpi-pico-serprog" ] || mkdir -p ${location%/*} || \
+	    fail "clone_project: cannot make directory for rpi-pico-serprog"
 	mv "${tmp_dir}" "${location}" || \
 	    fail "clone_project: could not copy temp file to destination"
 }