Use std::filesystem when generating callout paths
Use std::filesystem when generating callout paths

Change-Id: Ia4dbe7e27368a7136d3767f105f6af78d9627c3f
Signed-off-by: Brad Bishop <713d098c0be4c8fd2bf36a94cd08699466677ecd@fuzziesquirrel.com>

openbmc/phosphor-hwmon,openbmc/phosphor-hwmon