platform: andes/ae350: Use fdt irqchip driver

Andes PLIC is compatible with plic driver. The PLIC base address and
number of source can be obtained by parsing the device tree.

Signed-off-by: Yu Chien Peter Lin <peterlin@andestech.com>
Reviewed-by: Leo Yu-Chi Liang <ycliang@andestech.com>
Reviewed-by: Anup Patel <anup@brainfault.org>

platform/andes/ae350/Kconfig

@@ -3,13 +3,14 @@
 config PLATFORM_ANDES_AE350
 	bool
 	select FDT
-	select IRQCHIP_PLIC
 	select FDT_SERIAL
 	select FDT_SERIAL_UART8250
 	select FDT_TIMER
 	select FDT_TIMER_PLMT
 	select FDT_RESET
 	select FDT_RESET_ATCWDT200
+	select FDT_IRQCHIP
+	select FDT_IRQCHIP_PLIC
 	default y
 
 if PLATFORM_ANDES_AE350