Remove redundant BOARD_VNDK_VERSION

board/treble_common.mk already has the setting.

Bug: 76126824
Test: build aosp_arm64_ab-userdebug pass
Change-Id: I7e3680a1cb36c38bdb29564c39b17b9a16067e21
diff --git a/target/board/generic_arm64_ab/BoardConfig.mk b/target/board/generic_arm64_ab/BoardConfig.mk
index 00afee6..286a741 100644
--- a/target/board/generic_arm64_ab/BoardConfig.mk
+++ b/target/board/generic_arm64_ab/BoardConfig.mk
@@ -39,5 +39,3 @@
 # TODO(b/36764215): remove this setting when the generic system image
 # no longer has QCOM-specific directories under /.
 BOARD_SEPOLICY_DIRS += build/target/board/generic_arm64_ab/sepolicy
-
-BOARD_VNDK_VERSION := current