Fix offset to slot_suffix

slot_suffix has moved outside of bootloader_message.
Fixed up the offset which is now in bootloader_message_ab

BUG:29371681
Change-Id: Id90a1aa777dc9289dc5ba37655144e6d22ad3f2f
diff --git a/soc/common/boot_control/bootinfo.c b/soc/common/boot_control/bootinfo.c
index 8f5b214..6209a65 100644
--- a/soc/common/boot_control/bootinfo.c
+++ b/soc/common/boot_control/bootinfo.c
@@ -83,12 +83,12 @@
 	return fd;
 }
 
-// As per struct bootloader_message which is defined in
+// As per struct bootloader_message_ab which is defined in
 // bootable/recovery/bootloader.h we can use the 32 bytes in the
 // bootctrl_suffix field provided that they start with the active slot
 // suffix terminated by NUL. It just so happens that BrilloBootInfo is
 // laid out this way.
-#define BOOTINFO_OFFSET offsetof(struct bootloader_message, slot_suffix)
+#define BOOTINFO_OFFSET offsetof(struct bootloader_message_ab, slot_suffix)
 
 bool boot_info_load(BrilloBootInfo *out_info)
 {