Apply snapshot variant to vndk package module name

VNDK snapshot phony package, vndk_v$VER, is redefined to
separate phony packages per VNDK snapshot build variant,
vndk_v$VER_$VARIANT, where $VARIANT is defined as the primary
$TARGET_ARCH of the build target.

Accordingly, top level Android.bp file under prebuilts/vndk/v$VER
is redefined as separate Android.bp files for each snapshot
variant at prebuilts/vndk/v$VER/$VARIANT/Android.bp.

Test: m -j PRODUCT_EXTRA_VNDK_VERSIONS=27 (after installing
snapshot to prebuilts/vndk/v27)
Bug: 71370248

Change-Id: Ida449978090fe8a4f16376c991d34fa0945be596
diff --git a/core/envsetup.mk b/core/envsetup.mk
index 89a39a8..255c02b 100644
--- a/core/envsetup.mk
+++ b/core/envsetup.mk
@@ -287,7 +287,7 @@
 # Check BOARD_VNDK_VERSION
 define check_vndk_version
   $(eval vndk_path := prebuilts/vndk/v$(1)) \
-  $(if $(wildcard $(vndk_path)/Android.bp),,$(error VNDK version $(1) not found))
+  $(if $(wildcard $(vndk_path)/*/Android.bp),,$(error VNDK version $(1) not found))
 endef
 
 ifdef BOARD_VNDK_VERSION