Change linker config variable: VNDK_VER

With VNDK APEX, the path for VNDK libs has been changed
from /system/lib/vndk-VER to /apex/com.android.vndk.vVER/lib

Previously, VNDK_VER is replaced with prefix(e.g. "-29"). We could
still prepend prefix("v") to the vndk version, but this change uses a
raw vndk version as the value of VNKD_VER.

Bug: 141451661
Test: m && boot (tested with cuttlefish)
Change-Id: Ibf4cf5e29b7f28e733d4b3bc15171f4359e1d2f2
diff --git a/linker/linker_config.h b/linker/linker_config.h
index 75d9378..547c62e 100644
--- a/linker/linker_config.h
+++ b/linker/linker_config.h
@@ -164,7 +164,7 @@
                                  const Config** config,
                                  std::string* error_msg);
 
-  static std::string get_vndk_version_string(const char delimiter);
+  static std::string get_vndk_version_string(const std::string& prefix);
  private:
   void clear();