selftests/mm: fix check for running THP tests

When testing if we should try to compact memory or drop caches before we
run the THP or HugeTLB tests we use | as an or operator. This doesn't
work since run_vmtests.sh is written in shell where this is used to pipe
the output of the first argument into the second. Instead use the shell's
-o operator.

Link: https://lkml.kernel.org/r/[e-mail]
Fixes: b433ffa8dbac ("selftests: mm: perform some system cleanup before using hugepages")
Signed-off-by: Mark Brown <[e-mail]>
Reviewed-by: Nico Pache <[e-mail]>
Cc: Mariano Pache <[e-mail]>
Cc: Shuah Khan <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>

tools/testing/selftests/mm/run_vmtests.sh

···
 	if test_selected ${CATEGORY}; then
 		# On memory constrainted systems some tests can fail to allocate hugepages.
 		# perform some cleanup before the test for a higher success rate.
-		if [ ${CATEGORY} == "thp" ] | [ ${CATEGORY} == "hugetlb" ]; then
+		if [ ${CATEGORY} == "thp" -o ${CATEGORY} == "hugetlb" ]; then
 			echo 3 > /proc/sys/vm/drop_caches
 			sleep 2
 			echo 1 > /proc/sys/vm/compact_memory