misc: tegra-profiler: unwinding: use RCU locking

misc: tegra-profiler: unwinding: use RCU locking

Unwinding: use RCU locking instead of spinlocks to protect
map of regions.

Bug 1502205

Change-Id: If1089b74b1f317eeaae5059de40d7a3365ae4061
Signed-off-by: Igor Nabirushkin <inabirushkin@nvidia.com>
Reviewed-on: http://git-master/r/397599
(cherry picked from commit 3504dc62f0aad25ad5c50f46c6c3319b95775966)
Reviewed-on: http://git-master/r/454437
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Tested-by: Maxim Morin <mmorin@nvidia.com>
Reviewed-by: Mitch Luban <mluban@nvidia.com>