ptm: tegra210: set floor for cycle count threshold

ptm: tegra210: set floor for cycle count threshold

cycle count threshold can't be less than the minimum supported
by HW, otherwise the behavior is constraied unpredictable.

force cycle count threshold to be above HW minimum in TRCIDR3.

Change-Id: I7d25464d58eae0bc153b8e58086e4765f6c57e02
Signed-off-by: Bo Yan <byan@nvidia.com>
Reviewed-on: http://git-master/r/677867
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Mitch Luban <mluban@nvidia.com>
GVS: Gerrit_Virtual_Submit