[][openwrt][mt7988][eth][Add Ethernet RSS full support for Jaguar]

Add Ethernet RSS full support for Jaguar.
In the past, RSS events are assigned to FE interrupts (GIC_ID: 196~199);
currently, RSS events would be assigned to ADMA-dedicated
interrupts (GIC_ID: 189~192) instead. In this way, RSS won't be limited
by the number of FE interrupts anymore, and thus can be extended
to 4-RSS Rx rings.

If without this patch, Ethernet can only enable 2-RSS Rx rings
due to the limitation of FE interrupt number.

Assume IRQ numbers of Ethernet Rx interrupts are 124~127 (shown in
cat /proc/interrupts).
Then we can adjust smp affinity to decide which CPU is going to
process those Rx interrupts.
The below example shows how we utilize 3-CPU to process Rx interrupts.
   - echo 1 > /proc/irq/124/smp_affinity  (CPU0 processes IRQ 124)
   - echo 2 > /proc/irq/125/smp_affinity  (CPU1 processes IRQ 125)
   - echo 4 > /proc/irq/126/smp_affinity  (CPU2 processes IRQ 126)
   - echo 4 > /proc/irq/127/smp_affinity  (CPU2 processes IRQ 127)


Change-Id: I3df05df5863e9cb5288bb6db5113d3bc75ce46ad
Reviewed-on: https://gerrit.mediatek.inc/c/openwrt/feeds/mtk_openwrt_feeds/+/7514813
6 files changed