Fix conflicted skipping condition for test_pfc_asym

[bingwang-ms]

Description of PR

Summary:
Fixes conflicted skipping condition for test_pfc_asym.
Before this change, there are two skipping conditions.

#######################################
#####         pfc_asym            #####
#######################################
pfc_asym/test_pfc_asym.py:
  skip:
    reason: 'pfc_asym test skip except for on Barefoot platforms'
    conditions:
      - "asic_type not in ['barefoot']"

pfc_asym/test_pfc_asym.py::test_pfc_asym_off_rx_pause_frames:
   skip:
     reason: "skipped for Barefoot platform"
     conditions:
        - "asic_type in ['barefoot']"

This PR reomoved the second one as it has been covered by the first one.

Type of change

• Bug fix
• Testbed and Framework(new/improvement)
• Test case(new/improvement)

Back port request

• 202012
• 202205
• 202305
• 202311
• 202405

Approach

What is the motivation for this PR?

This PR is to fix conflicted skipping condition for test_pfc_asym.

How did you do it?

Remove the unused condition.

How did you verify/test it?

Verified by syntax check.

Any platform specific information?

No.

Supported testbed topology if it's a new test case?

Not a new test case.

Documentation

[mssonicbld]

Cherry-pick PR to 202405: #15371