wifi: iwlwifi: mask reserved bits in chan_state_active_bitmap

Mask the reserved bits as firmware will assert if reserved bits are set.

Fixes: ef7ddf4e ("wifi: iwlwifi: Add support for LARI_CONFIG_CHANGE_CMD v12")
Signed-off-by: Pagadala Yesu Anjaneyulu <pagadala.yesu.anjaneyulu@intel.com>
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Link: https://patch.msgid.link/20250709065608.7a72c70bdc9d.Ic9be0a3fc3aabde0c4b88568f3bb7b76e375f8d4@changeid