slot_metadata: add verity_corrupted field

In rootfs context, the verity mode must be supplied by the bootloader
to the kernel.  This patch creates a new verity_corrupted field in the
slot metadata structure to remind that this slot is corrupted from a
dm-verity point of view.

If the bootloader receives the "dm-verity device corrupted" reboot
target, it should set this bit to 1.  If this bit value is 1, the
bootloader should set the veritymode to "eio".

Change-Id: I9335a39d7d009200318c58c53a3139d542788a9b
Signed-off-by: Jeremy Compostella <jeremy.compostella@intel.com>

bootloader.h

@@ -74,8 +74,11 @@ struct slot_metadata {
     uint8_t tries_remaining : 3;
     // 1 if this slot has booted successfully, 0 otherwise.
     uint8_t successful_boot : 1;
+    // 1 if this slot is corrupted from a dm-verity corruption, 0
+    // otherwise.
+    uint8_t verity_corrupted : 1;
     // Reserved for further use.
-    uint8_t reserved;
+    uint8_t reserved : 7;
 } __attribute__((packed));
 
 /* Bootloader Control AB