cpuset_memory_pressure in controllers from ubuntu_ltp failed on Focal Power8 (TFAIL: set general group parameter failed.)

[Po-Hsu Lin]

Issue found on 5.4.0-49.53 Power8 node modoc

Test failed with:
 startup='Tue Sep 22 08:35:42 2020'
 cpuset_memory_pressure 1 TPASS: Cpuset memory pressure test succeeded.
 Killed
 cpuset_memory_pressure 3 TPASS: Cpuset memory pressure test succeeded.
 cpuset_memory_pressure 5 TINFO: /bin/echo: write error: Invalid argument
 cpuset_memory_pressure 5 TFAIL: set general group parameter failed.
 cpuset_memory_pressure 7 TINFO: /bin/echo: write error: Invalid argument
 cpuset_memory_pressure 7 TFAIL: set general group parameter failed.
 cpuset_memory_pressure 9 TINFO: /bin/echo: write error: Invalid argument
 cpuset_memory_pressure 9 TFAIL: set general group parameter failed.
 cpuset_memory_pressure 11 TINFO: /bin/echo: write error: Invalid argument
 cpuset_memory_pressure 11 TFAIL: set general group parameter failed.
 tag=cpuset_memory_pressure stime=1600763742 dur=72 exit=exited stat=1 core=no cu=434 cs=4653