[HIPIFY][fix] Delete canCompileHostAndDeviceInOneJob declaration as well

[ROCm/hip commit: 0c07b6b421]

projects/hip/hipify-clang/src/LLVMCompat.h

@@ -85,8 +85,6 @@ std::error_code real_path(const Twine &path, SmallVectorImpl<char> &output,
 
 bool pragma_once_outside_header();
 
-bool canCompileHostAndDeviceInOneJob();
-
 void RetainExcludedConditionalBlocks(clang::CompilerInstance &CI);
 
 bool CheckCompatibility();