device-lg-hammerhead: remove device-specific weston config

Just a minimal cleanup task my eye catched, since device-lg-hammerhead/weston.ini is currently exactly the same as postmarketos-ui-weston/weston.ini-default after 6e75a19c

I've tried to test to the best of my knowledge while familiarizing with pmOS build tools: manually removing the file from a live installation and rebooting works fine, re-building the patched package with pmbootstrap build is successful, but I don't know how to build rootfs with this patched package. Edit: aaah, apk info reports device-lg-hammerhead-5-r1 but still installs the device-lg-hammerhead-weston-5-r0 subpackage. How can I remove that from pmaports?