wifi: iwlwifi: unify Bz/Gl device configurations

All the configurations for the various Bz/Gl devices
are basically identical, except for Gl A-step and the
firmware filename prefixes.

Add some infrastructure to auto-generate the firmware
filename prefix based on the detected MAC step and
RF name/step, and remove all the unneeded configs.

This reduces the size of the iwlwifi module by ~9k:
 517582	  27111	    560	 545253	  851e5	drivers/net/wireless/intel/iwlwifi/iwlwifi.ko
 526885	  27083	    560	 554528	  87620	drivers/net/wireless/intel/iwlwifi/iwlwifi.ko

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230621130443.1dc121ba338f.I07d651516eb82cbaded4724ef30558a50f2fa866@changeid


Signed-off-by: Johannes Berg <johannes.berg@intel.com>