clk: tegra: Replace .round_rate() with .determine_rate()

Replace the .round_rate() callback with .determine_rate() which can
consider max_rate imposed by clk_set_max_rate() while rounding the clock
rate.

Note that if the .determine_rate() callback is defined it will be called
instead of the .round_rate() callback when calling clk_round_rate(). By
using .determine_rate(), the maximum rate returned when calling
clk_round_rate() is now limited by the current max_rate.

Signed-off-by: Rajkumar Kasirajan <rkasirajan@nvidia.com>
[jonathanh@nvidia.com: checkpatch fixes and commit message update]
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>