IWK_FH_TCSR_LOWER_BOUND
(IWK_FH_TCSR_LOWER_BOUND + 0x20 * _chnl)
(IWK_FH_TCSR_LOWER_BOUND + 0x20 * _chnl + 0x4)
(IWK_FH_TCSR_LOWER_BOUND + 0x20 * _chnl + 0x8)