ath10k: Add support for 64 bit htt rx ring cfg

WCN3900 target uses 64bit rx_ring_base_paddr and
fw_idx_shadow_reg_paddr fields in HTT rx ring cfg message.
These address points to the memory region where remote
ring empty buffers are allocated.
In order to add 64 bit htt rx ring cfg, define separate
64 bit htt rx ring cfg message and attach it in runtime
based on target_64bit hw param flag.

Signed-off-by: Govind Singh <govinds@qti.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>