ARM: tegra: power: Add LP1 cold low voltage parameter

ARM: tegra: power: Add LP1 cold low voltage parameter

Currently, if CONFIG_TEGRA_LP1_LOW_COREVOLTAGE is enabled,
we decrease core voltage to a level specified via lp1_core_volt_low
in each platform's board file.

Add another level, lp1_core_volt_low_cold, which will be used if
there's a low temperature core voltage floor set during LP1 entry.
Only one voltage floor exists for T30 and T114, so only one additional
low voltage entry has been added.

Bug 1261915

Change-Id: I614a4176b0bf68d6607a104a980d38589ebd3046
Signed-off-by: Daniel Solomon <daniels@nvidia.com>
Reviewed-on: http://git-master/r/216364
(cherry picked from commit b12e9b71552b89664dd8bdfc26e5e33cc9b45056)
Reviewed-on: http://git-master/r/226437
Reviewed-by: Mrutyunjay Sawant <msawant@nvidia.com>
Tested-by: Mrutyunjay Sawant <msawant@nvidia.com>