OMAP3: cpuidle: configure latencies/thresholds from board file

The CPUidle C state latencies and thresholds are dependent on various
board specific details.  This patch makes it possible to configure
these values from the respective board files.

omap3_pm_init_cpuidle() can now be optionally called from board files
to pass board specific cpuidle parameters.  If the board files do not
use this function to pass the params default values are used which
might cause higher consumption dur to wrong state selection by the
governor.

This patch only updates the 3430sdp board files to use
omap3_pm_init_cpuidle().

From Kalle, in addition to original patch from Rajendra:

Building without CONFIG_CPU_IDLE or CONFIG_PM causes build to fail if
cpu idle parameters are tried to pass using omap3_pm_init_cpuidle
function.

Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Signed-off-by: Kalle Jokiniemi <kalle.jokiniemi@digia.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>