qt: ensure that target dir exists before installing there

All of qt.mk's target installs ensure that their destinations exist,
except for /usr/lib.  So do the same for /usr/lib, for consistency,
and in case some combination of custom fs skeleton plus dependency
on Qt leads to installing without a pre-existing /usr/lib directory.

Signed-off-by: Danomi Manchego <danomimanchego123@gmail.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

package/qt/qt.mk

@@ -625,6 +625,7 @@ endef
 # Library installation
 ifeq ($(BR2_PACKAGE_QT_SHARED),y)
 define QT_INSTALL_TARGET_LIBS
+	mkdir -p $(TARGET_DIR)/usr/lib
 	for lib in $(QT_INSTALL_LIBS); do \
 		cp -dpf $(STAGING_DIR)/usr/lib/lib$${lib}.so.* $(TARGET_DIR)/usr/lib ; \
 	done