wifi: iwlwifi: use bc entries instead of bc table also for pre-ax210

iwlagn_scd_bc_tbl is used for pre-ax210 devices,
and iwl_gen3_bc_tbl_entry is used for ax210 and on. But there is no
difference between the the 22000 version and the AX210+ one.

In order to unify the two, as first step make iwlagn_scd_bc_tbl an entry
as well, and adjust the code. In a later patch both structures will be
unified.

Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20250511195137.645cd82ebf48.Iaa7e88179372d60ef31157e379737b5babe54012@changeid