[CMake] add_tablegen: Rename host tablegen to `${target}-host"

Since `llvm-min-tblgen` has been introduced, `llvm-min-tblgen-host`
would make more sense than `LLVM_HEADERS-tablegen-host`.

Depends on D146352

Differential Revision: https://reviews.llvm.org/D149343

Author: chapuni

llvm/cmake/modules/TableGen.cmake

@@ -168,8 +168,8 @@ macro(add_tablegen target project)
       build_native_tool(${target} ${project}_TABLEGEN_EXE DEPENDS ${target})
       set(${project}_TABLEGEN_EXE ${${project}_TABLEGEN_EXE} PARENT_SCOPE)
 
-      add_custom_target(${project}-tablegen-host DEPENDS ${${project}_TABLEGEN_EXE})
-      set(${project}_TABLEGEN_TARGET ${project}-tablegen-host PARENT_SCOPE)
+      add_custom_target(${target}-host DEPENDS ${${project}_TABLEGEN_EXE})
+      set(${project}_TABLEGEN_TARGET ${target}-host PARENT_SCOPE)
 
       # If we're using the host tablegen, and utils were not requested, we have no
       # need to build this tablegen.