systemd: Re-enable chvt as non-root user without polkit
systemd 245 introduced a regression in behavior where they removed
support for non-root users to chvt from a service file. This prevents
running compositors (e.g. weston) as any user other than root. The
intention is for polkit to be used to allow this (and in fact the
default polkit rules that ship with systemd allow this). However, polkit
is a huge dependency to bring in for an embedded system, and isn't
support by OE-core.
The patch has been proposed upstream to restore the previous behavior of
allowing a non-root user to chvt to unbreak the regression without
requiring polkit.
