sysutils/tmux-mem-cpu-load: Replace local patch with upstream version

3.5.0 required a patch against a build error. This commit replaces a
local patch for it with the version from upstream, which is
substantively the same except the local patch won't recognize more than
256 CPUs. I'm including a PORTREVISION bump in case you're running
tmux-mem-cpu-load on your 512-core machine.