drivers: interrupt_controller: do not set sgi type

The GICD_ICFGR0 register is read only because SGIs are always
edge-triggered.

Signed-off-by: Nils Bosbach <bosbach@ice.rwth-aachen.de>

drivers/interrupt_controller/intc_gic.c

@@ -113,6 +113,8 @@ void arm_gic_irq_set_priority(
 	int_grp = (irq / 16) * 4;
 	int_off = (irq % 16) * 2;
 
+	/* GICD_ICFGR0 is read-only; SGIs are always edge-triggered */
+	if (int_grp != 0) {
 		val = sys_read32(GICD_ICFGRn + int_grp);
 		val &= ~(GICD_ICFGR_MASK << int_off);
 		if (flags & IRQ_TYPE_EDGE) {
@@ -121,6 +123,7 @@ void arm_gic_irq_set_priority(
 
 		sys_write32(val, GICD_ICFGRn + int_grp);
 	}
+}
 
 unsigned int arm_gic_get_active(void)
 {