ARM: tegra: fix VBUS regulator GPIO polarity in DT

Commit 4c94c8b5 "ARM: tegra: update device trees for USB binding rework"
added regulator definitions for GPIO-controlled USB VBUS. However, none
of these contained the essential DT property enable-active-high. Add
this so that the regulator definitions are correct.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>