selftests: mm: fix the incorrect usage() info of khugepaged

The mount option of tmpfs should be huge=advise, not madvise which is not
supported and may mislead the users.

Link: https://lkml.kernel.org/r/20241015020257.139235-1-sunnanyong@huawei.com
Fixes: 1b03d0d5 ("selftests/vm: add thp collapse file and tmpfs testing")
Signed-off-by: Nanyong Sun <sunnanyong@huawei.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

tools/testing/selftests/mm/khugepaged.c

@@ -1091,7 +1091,7 @@ static void usage(void)
 	fprintf(stderr, "\n\t\"file,all\" mem_type requires kernel built with\n");
 	fprintf(stderr,	"\tCONFIG_READ_ONLY_THP_FOR_FS=y\n");
 	fprintf(stderr, "\n\tif [dir] is a (sub)directory of a tmpfs mount, tmpfs must be\n");
-	fprintf(stderr,	"\tmounted with huge=madvise option for khugepaged tests to work\n");
+	fprintf(stderr,	"\tmounted with huge=advise option for khugepaged tests to work\n");
 	fprintf(stderr,	"\n\tSupported Options:\n");
 	fprintf(stderr,	"\t\t-h: This help message.\n");
 	fprintf(stderr,	"\t\t-s: mTHP size, expressed as page order.\n");