Fix CMake build

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@155933 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/Driver/CMakeLists.txt

 clang_tablegen(Options.inc -gen-opt-parser-defs
   SOURCE Options.td
   TARGET ClangDriverOptions)
-
-clang_tablegen(CC1AsOptions.inc -gen-opt-parser-defs
-  SOURCE CC1AsOptions.td
-  TARGET ClangCC1AsOptions)