wifi: ath12k: rename HE capabilities setup/copy functions

Functions ath12k_mac_setup_he_cap() and ath12k_mac_copy_he_cap()
propagate HE and 6GHz capabilities to the userspace using an instance
of struct ieee80211_sband_iftype_data. This structure now has a new
member 'eht_cap' to include EHT capabilities as well.
Rename the above mentioned functions to indicate that their use is not
limited to HE.

Also, replace the local variable 'band' with 'sband' and reuse
'band' for the type enum nl80211_band.

Tested-on: QCN9274 hw2.0 PCI WLAN.WBE.1.0.1-00029-QCAHKSWPL_SILICONZ-1
Signed-off-by: Aloka Dixit <quic_alokad@quicinc.com>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/20230725224034.14045-2-quic_alokad@quicinc.com