I don’t believe you can change it in the Control Panel, but you can configure the display of time in the shell with an environment variable.
Check out this page on displaying different time zones in the shell:
If you wish, you could set up your shell to make such a time zone display change every time you log by adding that line in your profile. If you are using the default “bash” shell, that files is .bash_profile.
It would probably not be accurate to change the time zone for the use in the Control Panel anyway, as it is labeled "Current DreamHost Time: ", (and that should be the local time for “DreamHost”).