wifi: ath11k: Add TWT debugfs support for STA interface

Currently TWT debugfs files required for manually testing the
TWT feature are created only for the AP interfaces; these debugfs
hooks are also required for the station interfaces in order to
test the TWT feature manually, therefore create these debugfs
hooks for station iftype as well.

In the case of station interfaces, TWT is entirely handled in the
firmware based on input parameters passed to it during association
via TWT enable WMI command. In order to manually test this feature,
firmware expects to first disable the TWT feature and then send the
enable command with sta_cong_timer_ms parameter set to 0.
This is true for WCN6750, QCA6390 & WCN6855 hardwares.

Tested-on: WCN6750 hw1.0 AHB WLAN.MSL.1.0.1-00887-QCAMSLSWPLZ-1

Signed-off-by: Manikanta Pubbisetty <quic_mpubbise@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/20220720135150.22193-2-quic_mpubbise@quicinc.com