allwinner: Detect and output current SoC

So far we already support booting on two different SoCs, and we will
shortly add a third, so add some code to determine the current SoC type.
This can be later used to runtime detect certain properties.

Also print the SoC name to the console, to give valuable debug information.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
diff --git a/plat/allwinner/common/sunxi_bl31_setup.c b/plat/allwinner/common/sunxi_bl31_setup.c
index f5f91e3..e910ee5 100644
--- a/plat/allwinner/common/sunxi_bl31_setup.c
+++ b/plat/allwinner/common/sunxi_bl31_setup.c
@@ -64,6 +64,22 @@
 
 void bl31_platform_setup(void)
 {
+	const char *soc_name;
+	uint16_t soc_id = sunxi_read_soc_id();
+
+	switch (soc_id) {
+	case 0x1689:
+		soc_name = "A64/H64/R18";
+		break;
+	case 0x1718:
+		soc_name = "H5";
+		break;
+	default:
+		soc_name = "unknown";
+		break;
+	}
+	NOTICE("BL31: Detected Allwinner %s SoC (%04x)\n", soc_name, soc_id);
+
 	generic_delay_timer_init();
 
 	/* Configure the interrupt controller */