ARM: tegra: Port tegra to generic clock framework

This patch converts tegra clock code to generic clock framework in following way:
 - Implement clk_ops as required by generic clk framework. (tegraXX_clocks.c)
 - Use platform specific struct clk_tegra in clk_ops implementation instead of struct clk.
 - Initialize all clock data statically. (tegraXX_clocks_data.c)

Legacy framework did not have recalc_rate and is_enabled functions. Implemented these functions.
Removed init function. It's functionality is splitted into recalc_rate and is_enabled.

Static initialization is used since slab is not up in .init_early and clock
is needed to be initialized before clockevent/clocksource initialization.
Macros redefined for clk_tegra.

Also, single struct clk_tegra is used for all type of clocks (PLL, peripheral etc.). This
is to move quickly to generic common clock framework so that other dependent features will
not be blocked (such as DT binding).

Enabling COMMON_CLOCK config moved to ARCH_TEGRA since it is enabled for both Tegra20
and Tegra30.

Signed-off-by: Prashant Gaikwad <pgaikwad@nvidia.com>
Signed-off-by: Stephen Warren <swarren@nvidia.com>