No special treatment for vendor

Reviving INTRODUCED_IN macro for vendor builds so that they can use
__builtin_avialable() to guard new symbols.

Bug: 362658565
Test: m
Change-Id: Idbee60cb9dc30b09ca258240cded4967a1519dc9
diff --git a/libc/include/android/versioning.h b/libc/include/android/versioning.h
index 1676a72..1cf6e51 100644
--- a/libc/include/android/versioning.h
+++ b/libc/include/android/versioning.h
@@ -80,10 +80,3 @@
 #define __INTRODUCED_IN_32(api_level)
 #define __INTRODUCED_IN_64(api_level) __BIONIC_AVAILABILITY(introduced=api_level)
 #endif
-
-// Vendor and product modules do not follow SDK versioning. Ignore NDK guards for these modules.
-#if defined(__ANDROID_VNDK__)
-#undef __BIONIC_AVAILABILITY
-#define __BIONIC_AVAILABILITY(api_level, ...)
-#define __BIONIC_AVAILABILITY_GUARD(api_level) 1
-#endif // defined(__ANDROID_VNDK__)