rc.pvr.service not getting started

During some debugging of weston startup with the agl-image-weston image on the reference hardware, I realized that the rc.pvr.service systemd unit from the rcar3 BSP is not getting started as it adds itself of a dependency of weston@.service and not weston.service.  When AGL upgraded to Yocto kirkstone, it included an upstream change that switched to weston.service, so the BSP is now out of date.  We can work around this in meta-agl-bsp for now, the change will be tracked with this issue.