ARM: OMAP2+: clock: Remove all direct dereferencing of struct clk

While we move to Common Clk Framework (CCF), direct deferencing of struct
clk wouldn't be possible anymore. Hence get rid of all such instances
in the current clock code and use macros/helpers similar to the ones that
are provided by CCF.

While here also concatenate some strings split across multiple lines
which seem to be needed anyway.

Signed-off-by: Rajendra Nayak <rnayak@ti.com>
[paul@pwsan.com: simplified some compound expressions; reformatted some
 messages]
Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Mike Turquette <mturquette@linaro.org>