Split out the ELF kind from the InputFile Kind.

There were at least two issues with having them together:
* For compatibility checks, we only want to look at the ELF kind.
* Adding support for shared libraries should introduce one InputFile kind,
  not 4.

llvm-svn: 246707
diff --git a/lld/ELF/Driver.cpp b/lld/ELF/Driver.cpp
index 55c2412..843fa65 100644
--- a/lld/ELF/Driver.cpp
+++ b/lld/ELF/Driver.cpp
@@ -99,17 +99,17 @@
 
   // Write the result.
   ObjectFileBase &FirstObj = *Symtab.ObjectFiles[0];
-  switch (FirstObj.kind()) {
-  case InputFile::Object32LEKind:
+  switch (FirstObj.getELFKind()) {
+  case ELF32LEKind:
     writeResult<object::ELF32LE>(&Symtab);
     return;
-  case InputFile::Object32BEKind:
+  case ELF32BEKind:
     writeResult<object::ELF32BE>(&Symtab);
     return;
-  case InputFile::Object64LEKind:
+  case ELF64LEKind:
     writeResult<object::ELF64LE>(&Symtab);
     return;
-  case InputFile::Object64BEKind:
+  case ELF64BEKind:
     writeResult<object::ELF64BE>(&Symtab);
     return;
   }