wifi: mt76: mt7996: set correct beamformee SS capability

According to IEEE P802.11be/D6.0 Table 9-417n, beamformee SS field stands
for the maximum number of spatial streams that the STA can receive in an
EHT sounding NDP minus 1, and the minimum value of this field is 3.

This value indicates the decoding capability of a beamformee, which is
independent of current antenna settings. Correct the value for mt7996
and mt7992 chipsets based on their HW capability.

Signed-off-by: Howard Hsu <howard-yh.hsu@mediatek.com>
Signed-off-by: Shayne Chen <shayne.chen@mediatek.com>
Link: https://patch.msgid.link/20240816094635.2391-6-shayne.chen@mediatek.com


Signed-off-by: Felix Fietkau <nbd@nbd.name>