this is to be used with the disk-size config option, a user has to set. crc config set disk-size 35 then crc config set persistent-volume-size 4 can be set as default disk size in 31G and the extra increase of 4G can now be used for increasing the topolvm partition

this config option is currently only used with microshift preset but after #4117 is resolved will also be used for the openshift preset