wifi: mt76: mt7996: fix fw loading timeout

wifi: mt76: mt7996: fix fw loading timeout

Fix the following firmware loading error due to a wrong dma register
configuration if wed is disabled.

[    8.245881] mt7996e_hif 0001:01:00.0: assign IRQ: got 128
[    8.251308] mt7996e_hif 0001:01:00.0: enabling device (0000 -> 0002)
[    8.257674] mt7996e_hif 0001:01:00.0: enabling bus mastering
[    8.263488] mt7996e 0000:01:00.0: assign IRQ: got 126
[    8.268537] mt7996e 0000:01:00.0: enabling device (0000 -> 0002)
[    8.274551] mt7996e 0000:01:00.0: enabling bus mastering
[   28.648773] mt7996e 0000:01:00.0: Message 00000010 (seq 1) timeout
[   28.654959] mt7996e 0000:01:00.0: Failed to get patch semaphore
[   29.661033] mt7996e: probe of 0000:01:00.0 failed with error -11

Suggested-by: Sujuan Chen" <sujuan.chen@mediatek.com>
Fixes: 4920a3a1285f ("wifi: mt76: mt7996: set DMA mask to 36 bits for boards with more than 4GB of RAM")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>