cmds/pflask: support unprivileged use
cmds/pflask: support unprivileged use

Signed-off-by: Minux <72d850dbd8858b791995463d8539b5a379577f28@golang.org>

hugelgupf/u-root,GanShun/u-root,rminnich/u-root,u-root/u-root,GanShun/u-root,hugelgupf/u-root,u-root/u-root,rminnich/u-root,GanShun/u-root,hugelgupf/u-root,rminnich/u-root,hugelgupf/u-root,rminnich/u-root,u-root/u-root