mwifiex: Send DELBA requests according to spec

While looking at on-air packets using Wireshark, I noticed we're never
setting the initiator bit when sending DELBA requests to the AP: While
we set the bit on our del_ba_param_set bitmask, we forget to actually
copy that bitmask over to the command struct, which means we never
actually set the initiator bit.

Fix that and copy the bitmask over to the host_cmd_ds_11n_delba command
struct.

Fixes: 5e6e3a92 ("wireless: mwifiex: initial commit for Marvell mwifiex driver")
Signed-off-by: Jonas Dreßler <verdre@v0yd.nl>
Acked-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20211016153244.24353-5-verdre@v0yd.nl