exceptions_panic: Fix wrong PSCI function ID

Use the right literal for a PSCI_SYSTEM_RESET.

Fixes: d40ff91f658d ("vmbase: Handle very early exceptions")
Bug: 237659918
Test: m crosvm
Change-Id: I7df28e537191441628273510526ce4f839ed40e4
diff --git a/vmbase/exceptions_panic.S b/vmbase/exceptions_panic.S
index 6f73da8..4a3f2db 100644
--- a/vmbase/exceptions_panic.S
+++ b/vmbase/exceptions_panic.S
@@ -22,8 +22,8 @@
  */
 
 .macro exception_panic
-	mov	x0, 0x80400000
-	add	x0, x0, 9
+	mov	x0, 0x84000000
+	movk	x0, 9
 	mov	x1, 0
 	mov	x2, 0
 	mov	x3, 0