pci: tegra: trigger ltssm trace in loopback test

pci: tegra: trigger ltssm trace in loopback test

Enable ltssm trace and set trigger on loopback states.

Bug 1702230

Change-Id: If086d60113c993cabce877c5d032d14bb66afaf3
Signed-off-by: Ken Chang <kenc@nvidia.com>
Reviewed-on: http://git-master/r/840882
Reviewed-on: http://git-master/r/928195
(cherry picked from commit da42cda2fbba6767ae6f1b413ad2a363c6b28c00)
Reviewed-on: http://git-master/r/935555
(cherry picked from commit 6bb06c8d230d7373f8212d862c963319a6957b4c)
Reviewed-on: http://git-master/r/1011796
(cherry picked from commit 4f9e984451490fd28648dcfb3c5a767d26a91dc0)