arm: tegra: fuse: refactor driver for pgm2 value

arm: tegra: fuse: refactor driver for pgm2 value

Add an explicit function instead of the pre-defined table
to calculate the value of FUSETIME_PGM2 register.

PGM_TIME_US is defined for the fuse programming pulse:
 - for T114, T124 and T148, this is set to 12us.
 - for T30 and T20, this is set to 10us.

Change-Id: I6e276124bb5fb5081e085b23ed8c4bb7c0f87c5f
Signed-off-by: Ken Chang <kenc@nvidia.com>
Reviewed-on: http://git-master/r/263001
Reviewed-by: Marc Delvaux <mdelvaux@nvidia.com>
Reviewed-by: Bharat Nihalani <bnihalani@nvidia.com>