ath11k: configure RDDM size to mhi for recovery by firmware

The rddm_size is needed by firmware while mhi enter RDDM state, add it
to support recovery when ath11k receive MHI_CB_EE_RDDM message.

Tested-on: WCN6855 hw2.0 PCI WLAN.HSP.1.1-03003-QCAHSPSWPL_V1_V2_SILICONZ_LITE-2

Signed-off-by: Wen Gong <quic_wgong@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/20220209060012.32478-4-quic_wgong@quicinc.com