arm: tegra: tn8: change voltmon (OC1) throttling

arm: tegra: tn8: change voltmon (OC1) throttling

Change OC1 (voltage monitor) throttling parameters on P1761
platforms. New values:
 - Throttling depth 75%
 - Ramp rate 3.76us

While at it, also fix voltmon_oc1 and batmon_oc4 structures to be
static.

Bug 1444676

Change-Id: I2dee90db845b71704abc9e77c119081c2964332b
Signed-off-by: Timo Alho <talho@nvidia.com>
Reviewed-on: http://git-master/r/359870
(cherry picked from commit 3a13c642841f8c2b6819b012079769c7d2b752df)
Reviewed-on: http://git-master/r/362847
Reviewed-by: Juha Tukkinen <jtukkinen@nvidia.com>
Tested-by: Juha Tukkinen <jtukkinen@nvidia.com>