thunderbolt: Reserve released DisplayPort bandwidth for a group for 10 seconds

The USB4 spec says that the Connection Manager should reserve the
bandwidth that is released in the same group for 10 seconds before it
can be shared with other groups. Add support for this. We also delay the
symmetric transition by that same 10 seconds to avoid any unnecessary
transitions (i.e if the released bandwidth is used by another
DisplayPort tunnel in the same group the link can stay asymmetric the
whole time).

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>