EHT: Use HE operating channel width in MCS length calculation

EHT: Use HE operating channel width in MCS length calculation

Channel width in HE Capabilities element added to management frames is
calculated in hostapd_eid_he_capab() by intersecting the driver
capabilities and the operating channel width. Kernel uses this value
from the Beacon frames to verify EHT capabilities length. However, EHT
MCS length calculation uses only the driver capabilities which results
in EHT AP bring up failure in some cases dues to different lengths.

Modify the EHT code to use the HE operating channel width as well to
determine matching length for the information.

Signed-off-by: Aloka Dixit <quic_alokad@quicinc.com>