keyboardio-builder: Drop the extra build args

There is no `libraries/` in the core firmware anymore, do not add that to the
library search path.

Signed-off-by: Gergely Nagy <algernon@madhouse-project.org>

.keyboardio-builder.conf

@@ -8,6 +8,5 @@ generate_keymaps () {
             ( find . -type f | sort | xargs -n 1 -I % sh -c 'perl ../../../tools/generate_keymaps.pl < % >> ../generated/keymaps.h' ))
 }
 
-EXTRA_BUILDER_ARGS="-libraries ${SOURCEDIR}/libraries"
 DEFAULT_SKETCH=KeyboardioFirmware
 compile_HOOKS="generate_keymaps"