onclite: Enable AVB and Set BOARD_AVB_ROLLBACK_INDEX.

It encodes PLATFORM_SECURITY_PATCH as the AVB rollback index.

Bug: 78463994
Test: Build with blueline-userdebug. Check the rollback index with
      `avbtool info_image --image $OUT/vbmeta.img`.
Test: Flash and boot into on B1.
Change-Id: Iea02c939d1090e630a36660ea7809273f6724002
Signed-off-by: Dhina17 <dhinalogu@gmail.com>

BoardConfig.mk

@@ -37,6 +37,10 @@ TARGET_USES_64_BIT_BINDER := true
 
 BUILD_BROKEN_DUP_RULES := true
 
+# AVB
+BOARD_AVB_ENABLE := true
+BOARD_AVB_ROLLBACK_INDEX := $(PLATFORM_SECURITY_PATCH_TIMESTAMP)
+
 # Kernel
 BOARD_KERNEL_BASE := 0x80000000
 BOARD_KERNEL_CMDLINE := console=ttyMSM0,115200,n8 androidboot.console=ttyMSM0 androidboot.hardware=qcom msm_rtb.filter=0x237 ehci-hcd.park=3 lpm_levels.sleep_disabled=1 androidboot.bootdevice=7824900.sdhci earlycon=msm_serial_dm,0x78af000 firmware_class.path=/vendor/firmware_mnt/image androidboot.usbconfigfs=true loop.max_part=7