ARM: OMAP2: clock: Convert to common clk

Convert all OMAP2 specific platform files to use COMMON clk
and keep all the changes under the CONFIG_COMMON_CLK macro check
so it does not break any existing code. At a later point switch
to COMMON clk and get rid of all old/legacy code.

Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Mike Turquette <mturquette@ti.com>
[paul@pwsan.com: updated to apply]
Signed-off-by: Paul Walmsley <paul@pwsan.com>