[SYCL][HIP] Add cl_khr_fp64 in device extensions (#7428)

HIP plugin didn't have `cl_khr_fp64` in SupportedExtensions, so any
kernel uses fp64 cannot be launched because
`ProgramManager::getBuiltPIProgram` checks `has(aspect::fp64)` which is
actually `has_extension("cl_khr_fp64")`.

sycl/plugins/hip/pi_hip.cpp

@@ -1659,6 +1659,13 @@ pi_result hip_piDeviceGetInfo(pi_device device, pi_device_info param_name,
     SupportedExtensions += PI_DEVICE_INFO_EXTENSION_DEVICELIB_ASSERT;
     SupportedExtensions += " ";
 
+    hipDeviceProp_t props;
+    sycl::detail::pi::assertion(hipGetDeviceProperties(&props, device->get()) ==
+                                hipSuccess);
+    if (props.arch.hasDoubles) {
+      SupportedExtensions += "cl_khr_fp64 ";
+    }
+
     return getInfo(param_value_size, param_value, param_value_size_ret,
                    SupportedExtensions.c_str());
   }