This adds hub_set_power_budget(), mostly so that HCDs for low
powered ports (cell phone, PDA, etc) can more easily report their
true power budgets.  It's not always 500mA per root hub port; this
makes dummy_hcd report the minimum, 8mA.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>