mt76: mt7603: fix initialization of max rx length

The previous version only accidentally disabled A-MSDU deaggregation by
using the wrong mask for rx length configuration, which left previous
length value in place.
Fix the length and initialize the register completely to keep A-MSDU
de-aggregation remaining disabled
Signed-off-by: Felix Fietkau <nbd@nbd.name>

drivers/net/wireless/mediatek/mt76/mt7603/init.c

@@ -167,7 +167,8 @@ mt7603_mac_init(struct mt7603_dev *dev)
 		FIELD_PREP(MT_AGG_RETRY_CONTROL_BAR_LIMIT, 1) |
 		FIELD_PREP(MT_AGG_RETRY_CONTROL_RTS_LIMIT, 15));
 
-	mt76_rmw(dev, MT_DMA_DCR0, ~0xfffc, 4096);
+	mt76_wr(dev, MT_DMA_DCR0, MT_DMA_DCR0_RX_VEC_DROP |
+		FIELD_PREP(MT_DMA_DCR0_MAX_RX_LEN, 4096));
 
 	mt76_rmw(dev, MT_DMA_VCFR0, BIT(0), BIT(13));
 	mt76_rmw(dev, MT_DMA_TMCFR0, BIT(0) | BIT(1), BIT(13));

drivers/net/wireless/mediatek/mt76/mt7603/regs.h

@@ -233,6 +233,10 @@
 #define MT_WF_DMA(ofs)			(MT_WF_DMA_BASE + (ofs))
 
 #define MT_DMA_DCR0			MT_WF_DMA(0x000)
+#define MT_DMA_DCR0_MAX_RX_LEN		GENMASK(15, 0)
+#define MT_DMA_DCR0_DAMSDU		BIT(16)
+#define MT_DMA_DCR0_RX_VEC_DROP		BIT(17)
+
 #define MT_DMA_DCR1			MT_WF_DMA(0x004)
 
 #define MT_DMA_FQCR0			MT_WF_DMA(0x008)