OMAP2+: hwmod: add postsetup state

OMAP2+: hwmod: add postsetup state

Allow board files and OMAP core code to control the state that some or
all of the hwmods end up in at the end of _setup() (called by
omap_hwmod_late_init() ).  Reimplement the old skip_setup_idle code in
terms of this new postsetup state code.

There are two use-cases for this patch: the !CONFIG_PM_RUNTIME case,
in which all IP blocks should stay enabled after _setup() finishes;
and the MPU watchdog case, in which the watchdog IP block should enter
idle if watchdog coverage of kernel initialization is desired, and
should be disabled otherwise.

Signed-off-by: Paul Walmsley <paul@pwsan.com>
Cc: Benoît Cousson <b-cousson@ti.com>
Cc: Kevin Hilman <khilman@deeprootsystems.com>
Cc: Charulatha Varadarajan <charu@ti.com>