wilc1000: Rename irq handler from "WILC_IRQ" to netdev name

This change follows normal Linux convention and the new name is more
useful since it'll be clear which irq handler statistics correspond to
which net device.

Signed-off-by: David Mosberger-Tang <davidm@egauge.net>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20211209044411.3482259-3-davidm@egauge.net