Fix register usage of SPCI_ERROR.

Bug: 141469322
Change-Id: Ic0e0de74e905ca02e42778d3e17cfb194758380b
diff --git a/main.c b/main.c
index e3cf9af..758b965 100644
--- a/main.c
+++ b/main.c
@@ -573,7 +573,7 @@
 	spin_unlock_irqrestore(&hf_send_lock, flags);
 
 	if (ret.func == SPCI_ERROR_32) {
-		switch (ret.arg1) {
+		switch (ret.arg2) {
 		case SPCI_INVALID_PARAMETERS:
 			return -ENXIO;
 		case SPCI_NOT_SUPPORTED: