wifi: mt76: mt7915: fallback to non-wed mode if platform_get_resource fails in mt7915...

wifi: mt76: mt7915: fallback to non-wed mode if platform_get_resource fails in mt7915_mmio_wed_init()

mt76 assumes mt7915_mmio_wed_init can fail just after wed driver has
been attached running mtk_wed_device_attach().
Fall back to non-wed mode if platform_get_resource fails in
mt7915_mmio_wed_init routines.

Fixes: eebb70976be5 ("wifi: mt76: mt7915: enable wed for mt7986-wmac chipset")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Felix Fietkau <nbd@nbd.name>