Revert "[OpenCL] Add support for cslice partitioning (#7963)" (#8251)

This reverts commit dcbd6e5.

Author: dm-vodopyanov

sycl/plugins/opencl/CMakeLists.txt

@@ -10,22 +10,12 @@
 #TODO: Currently, the pi.h header is common between sycl and plugin library sources.
 #This can be changed by copying the pi.h file in the plugins project.
 
-find_package(Threads REQUIRED)
-
 add_sycl_plugin(opencl
   SOURCES
-    "../unified_runtime/pi2ur.hpp"
-    "../unified_runtime/pi2ur.cpp"
-    "../unified_runtime/ur/ur.hpp"
-    "../unified_runtime/ur/ur.cpp"
     "${sycl_inc_dir}/sycl/detail/pi.h"
     "pi_opencl.cpp"
-  INCLUDE_DIRS
-    ${CMAKE_CURRENT_SOURCE_DIR}/../unified_runtime # for Unified Runtime
   LIBRARIES
     OpenCL-ICD
-    Threads::Threads
-    UnifiedRuntime-Headers
 )
 
 set_target_properties(pi_opencl PROPERTIES LINKER_LANGUAGE CXX)