clk: tegra114: add LP1 suspend/resume support

When the system suspends to LP1, the CPU clock source is switched to
CLK_M (12MHz Oscillator) during suspend/resume flow. The CPU clock
source is controlled by the CCLKG_BURST_POLICY register, and hence this
register must be restored during LP1 resume.

Cc: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Joseph Lo <josephl@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>