util/osdep: Remove some early cruft

util/osdep: Remove some early cruft

The include for statvfs.h has not been needed since all statvfs calls
were removed in commit 4a1418e07bdc ("Unbreak large mem support by
removing kqemu").

The comment mentioning CONFIG_BSD hasn't made sense since an include
for config-host.h was removed in commit aafd75841001 ("util: Clean up
includes").

Remove this cruft.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Andrew Deason <adeason@sinenomine.net>
Message-id: 20220316035227.3702-4-adeason@sinenomine.net
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>