misc: tegra-profiler: fix debug preempt warnings

misc: tegra-profiler: fix debug preempt warnings

Tegra Profiler: fix warnings with CONFIG_DEBUG_PREEMPT=y

* Add the missing preempt_disable/enable() pairs in start/stop ioctls.
* Untie mmap and some other samples from the current cpu.

Bug 200067410
Bug 1598009

Change-Id: I9f03facf3a0ecee20432019ea8094a349c7897d1
Signed-off-by: Igor Nabirushkin <inabirushkin@nvidia.com>
Reviewed-on: http://git-master/r/668123
(cherry picked from commit ee3374eb9983d1ccadbf3a54c977d3e6db97ec4a)
Reviewed-on: http://git-master/r/672042
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Venkat Moganty <vmoganty@nvidia.com>