dt-bindings: net: mediatek,net: allow up to 8 IRQs

dt-bindings: net: mediatek,net: allow up to 8 IRQs

Increase the maximum IRQ count to 8 (4 FE + 4 RSS/LRO).

Frame-engine-IRQs (max 4):
MT7621, MT7628: 1 FE-IRQ
MT7622, MT7623: 3 FE-IRQs (only two used by the driver for now)
MT7981, MT7986, MT7988: 4 FE-IRQs (only two used by the driver for now)

Mediatek Filogic SoCs (mt798x) have 4 additional IRQs for RSS and/or
LRO. So MT798x have 8 IRQs in total.

MT7981 does not have a ethernet-node yet.
MT7986 Ethernet node is updated with RSS/LRO IRQs in this series.
MT7988 Ethernet node is added in this series.

Signed-off-by: Frank Wunderlich <frank-w@public-files.de>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://patch.msgid.link/20250709111147.11843-3-linux@fw-web.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>