Remove imm cmdlist workaround (#2523)

Signed-off-by: Gu, Jinghui <jinghui.gu@intel.com>

Author: gujinghui

intel_extension_for_pytorch/xpu/__init__.py

@@ -31,14 +31,6 @@
 default_generators: Tuple[torch._C.Generator] = ()
 _device_t = Union[_device, str, int]
 
-# Start of imm cmdlist workaround
-# Switch to immediate command list in LevelZero plugin to avoid resource leak.
-# The immediate command list will be default in next version of plugin.
-# Then, this workaround will be removed soon.
-import os
-# Enable immediate cmdlist by default
-os.environ['SYCL_PI_LEVEL_ZERO_USE_IMMEDIATE_COMMANDLISTS']="1"
-# End of imm cmdlist workaround
 
 def is_initialized():
     r"""Returns whether XPU state has been initialized."""