hw/occ: Fix OCC structure layout

POWER10 addition accidentally changed a structure size by one byte.

Fixes: c8c36ada1d9a ("occ: Add POWER10 support")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Reza Arbab <arbab@linux.ibm.com>

hw/occ.c

diff --git a/hw/occ.c b/hw/occ.c
index bf2b2f9..0a02d83 100644
--- a/hw/occ.c
+++ b/hw/occ.c
@@ -261,12 +261,14 @@
 	u8 major_version;
 	u8 minor_version;
 	u8 gpus_present;
-	struct __packed { /* Version 0x90 */
-		u8 spare1;
-	} v9;
-	struct __packed { /* Version 0xA0 */
-		u8 wof_enabled;
-	} v10;
+	union __packed {
+		struct __packed { /* Version 0x90 */
+			u8 spare1;
+		} v9;
+		struct __packed { /* Version 0xA0 */
+			u8 wof_enabled;
+		} v10;
+	};
 	u8 cpu_throttle;
 	u8 mem_throttle;
 	u8 quick_pwr_drop;