sysutils/py-psutil: Fix failing __FreeBSD_version check

• Bump PORTREVISION for package change

psutil 5.9.1 does not include <sys/param.h> in arch/freebsd/mem.c, causing the
__FreeBSD_version check there not not work properly and thus breaking the port
on systems without COMPAT_FREEBSD7.

PR: 264807
Reference: https://github.com/giampaolo/psutil/issues/2113