net: dsa: microchip: Initialize IRQ's mask outside common_setup()

net: dsa: microchip: Initialize IRQ's mask outside common_setup()

The IRQ logic of the KSZ8463 differs from that of other KSZ switches.
It doesn't have a 'mask' register but an 'enable' one instead. The
common IRQ framework can still be used though as soon as we reverse
the logic (using '1' to enable interrupts instead of '0') for KSZ8463
cases.

Move the initialization of the kirq->masked outside of
ksz_irq_common_setup() to keep this function truly common when
IRQ support for the KSZ8463 is added.

Signed-off-by: Bastien Curutchet (Schneider Electric) <bastien.curutchet@bootlin.com>
Link: https://patch.msgid.link/20260105-ksz-rework-v1-1-a68df7f57375@bootlin.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>