allwinner: Merge duplicate code in sunxi_power_down

The action of last resort isn't going to change between SoCs. This moves
that code back to the PSCI implementation, where it more obviously
matches the code in sunxi_system_reset().

The two error messages say essentially the same thing anyway.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Change-Id: I62ac35fdb5ed78a016e9b18281416f1dcea38a4a
diff --git a/plat/allwinner/sun50i_a64/sunxi_power.c b/plat/allwinner/sun50i_a64/sunxi_power.c
index b0d0427..b6437ea 100644
--- a/plat/allwinner/sun50i_a64/sunxi_power.c
+++ b/plat/allwinner/sun50i_a64/sunxi_power.c
@@ -322,7 +322,7 @@
 	return 0;
 }
 
-void __dead2 sunxi_power_down(void)
+void sunxi_power_down(void)
 {
 	switch (pmic) {
 	case GENERIC_H5:
@@ -368,8 +368,4 @@
 		break;
 	}
 
-	udelay(1000);
-	ERROR("PSCI: Cannot turn off system, halting.\n");
-	wfi();
-	panic();
 }