OMAP2 clock: add clk.prcm_mod field; annotate OMAP2xxx clocks

OMAP2 clock: add clk.prcm_mod field; annotate OMAP2xxx clocks

Add a "prcm_mod" field to the struct clk in OMAP2/3, and annotate each
OMAP2xxx real hardware clock controlled by the PRCM with the PRCM
module offset.  (A subsequent patch will annotate OMAP3 clocks.)

Add flags for this field that allow the registers to
be marked as existing in the PRM, CM, or System Control Module.

A subsequent patch will use this to simplify register addressing in the
struct clk.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>