onclite: AVB: Don't set rollback index

* Rollback protection is useless when device bootloader is UNLOCKED.
  In UNLOCKED state,rollback failures are allowed.

* In UNLOCKED state,even rollback stored_rollback_index[n] on the device won't be updated with flag values.
  But Sadly the timestamp of the SPL still persists on device's devinfo even when you erase that.

* Unlike Pixel Devices,MIUI doesn't set any SPL timestamp to enforce rollback protection.
  So Unfortunately,Because of these reasons users can't relock their device bootloader with stock MIUI.
  So Drop this to save upcoming  users.

Signed-off-by: Dhina17 <dhinalogu@gmail.com>
Change-Id: I35d541a77168d67824beb6dc644de3491b2f9e50

BoardConfig.mk

@@ -39,7 +39,6 @@ BUILD_BROKEN_DUP_RULES := true
 # AVB
 BOARD_AVB_ENABLE := true
 BOARD_AVB_MAKE_VBMETA_IMAGE_ARGS += --set_hashtree_disabled_flag
-BOARD_AVB_ROLLBACK_INDEX := $(PLATFORM_SECURITY_PATCH_TIMESTAMP)
 
 # Kernel
 BOARD_KERNEL_BASE := 0x80000000