wifi: mt76: mt7996: fix the capability of reception of EHT MU PPDU

wifi: mt76: mt7996: fix the capability of reception of EHT MU PPDU

This commit includes two changes. First, enable "EHT MU PPDU With 4x
EHT-LTF And 0.8us GI" in EHT Phy capabilities element since hardware
can support. Second, fix the value of "Maximum number of supported
EHT LTFs" in the same element, where the previous setting of 3 in
Bit 3-4 was incorrect.

Fixes: 348533eb968d ("wifi: mt76: mt7996: add EHT capability init")
Signed-off-by: Howard Hsu <howard-yh.hsu@mediatek.com>
Signed-off-by: Shayne Chen <shayne.chen@mediatek.com>
Link: https://patch.msgid.link/20250114101026.3587702-2-shayne.chen@mediatek.com
Signed-off-by: Felix Fietkau <nbd@nbd.name>