clk: ti: divider: Add the table parsing to get the best divider value

Currently the divider selection logic blindly divides the parent_rate
by the clk rate and gives the divider value for the divider clocks
which do not have the CLK_SET_RATE_PARENT flag set. Add the clk divider
table parsing to get the closest divider available in the table
provided via Device tree.

The code is pretty much taken from: drivers/clk/clk-divider.c.
and used here to fix up the best divider selection logic.

Signed-off-by: Keerthy <j-keerthy@ti.com>
Reported-by: Richard Woodruff <r-woodruff2@ti.com>
Acked-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>