Use uint16_t instead of size_t for symbol version ID.

Because it is uint16_t in the ELF spec. Using size_t was confusing.

llvm-svn: 287198
diff --git a/lld/ELF/LinkerScript.cpp b/lld/ELF/LinkerScript.cpp
index 778165c..f266b44 100644
--- a/lld/ELF/LinkerScript.cpp
+++ b/lld/ELF/LinkerScript.cpp
@@ -1802,7 +1802,7 @@
 void ScriptParser::readVersionDeclaration(StringRef VerStr) {
   // Identifiers start at 2 because 0 and 1 are reserved
   // for VER_NDX_LOCAL and VER_NDX_GLOBAL constants.
-  size_t VersionId = Config->VersionDefinitions.size() + 2;
+  uint16_t VersionId = Config->VersionDefinitions.size() + 2;
   Config->VersionDefinitions.push_back({VerStr, VersionId});
 
   if (consume("global:") || peek() != "local:")