powerpc/xics: Set the IRQ chip data for the ICS native backend

The ICS native driver relies on the IRQ chip data to find the struct
'ics_native' describing the ICS controller but it was removed by commit
248af248 ("powerpc/xics: Rename the map handler in a check handler").
Revert this change to fix the Microwatt SoC platform.

Fixes: 248af248 ("powerpc/xics: Rename the map handler in a check handler")
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Tested-by: Gustavo Romero <gustavo.romero@linaro.org>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210913134056.3761960-1-clg@kaod.org

arch/powerpc/sysdev/xics/xics-common.c

@@ -348,9 +348,9 @@ static int xics_host_map(struct irq_domain *domain, unsigned int virq,
 	if (xics_ics->check(xics_ics, hwirq))
 		return -EINVAL;
 
-	/* No chip data for the XICS domain */
+	/* Let the ICS be the chip data for the XICS domain. For ICS native */
 	irq_domain_set_info(domain, virq, hwirq, xics_ics->chip,
-			    NULL, handle_fasteoi_irq, NULL, NULL);
+			    xics_ics, handle_fasteoi_irq, NULL, NULL);
 
 	return 0;
 }