kselftest/cgroup: Fix gathering number of CPUs
test_cpuset_prs.sh is failing with the following error:
test_cpuset_prs.sh: line 29: [[: 8
57%: syntax error in expression (error token is "57%")
This is happening because `lscpu | grep "^CPU(s)"` returns two lines in
some systems (such as Debian unstable):
# lscpu | grep "^CPU(s)"
CPU(s): 8
CPU(s) scaling MHz: 55%
This is a simple fix that discard the second line.
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Kamalesh Babulal <kamalesh.babulal@oracle.com>
Signed-off-by: Tejun Heo <tj@kernel.org>