It has been found that the calibration files, while not mandatory, could be useful with the mainline mwifiex driver as well. Install those on mainline as well and leave the -downstream subpackage as a stub for -downstream-openrc. Also, switch from installing the firmware to /usr/lib instead of /lib to suppress warnings. Signed-off-by: Duje Mihanović <duje@dujemihanovic.xyz> Part-of: <https://gitlab.postmarketos.org/postmarketOS/pmaports/-/merge_requests/8311>