removed USING_ONEAPI_DPCPP in FindIntelSycl.cmake as it is unused

Author: oleksandr-pavlyk

dpctl-capi/cmake/modules/FindIntelSycl.cmake

@@ -38,7 +38,6 @@ include(FindPackageHandleStandardArgs)
 # IntelSycl_ROOT to that path.
 if(DPCTL_DPCPP_HOME_DIR)
     set(IntelSycl_ROOT ${DPCTL_DPCPP_HOME_DIR})
-    set(USING_ONEAPI_DPCPP False)
     message(STATUS "Not using standard oneAPI installation, but IntelSycl at " ${IntelSycl_ROOT})
 # If DPC++ installation was not specified, check for ONEAPI_ROOT
 elseif(DEFINED ENV{ONEAPI_ROOT})
@@ -49,7 +48,6 @@ elseif(DEFINED ENV{ONEAPI_ROOT})
     else()
         message(FATAL_ERROR "Unsupported system.")
     endif()
-    set(USING_ONEAPI_DPCPP True)
 else()
     message(FATAL_ERROR,
         "Could not locate a DPC++ installation. Either pass the path to a "