wifi: mt76: mt7925: introduce MLO capability control

wifi: mt76: mt7925: introduce MLO capability control

This patch introduces MLO capability control for the MT792x Wi-Fi driver.
It removes the unused `MT792x_CHIP_CAP_MLO_EVT_EN` flag and introduces new
capability flags `MT792x_CHIP_CAP_MLO_EN` and `MT792x_CHIP_CAP_MLO_EML_EN`
to enable MLO and EML features based on firmware capabilities.

Signed-off-by: Ming Yen Hsieh <mingyen.hsieh@mediatek.com>
Reviewed-by: Sabeeh Khan <sabeeh-khan@ti.com>
Link: https://patch.msgid.link/20250217081729.1840930-1-mingyen.hsieh@mediatek.com
Signed-off-by: Felix Fietkau <nbd@nbd.name>