staging: ti-soc-thermal: report alert events on OMAP4 devices

OMAP4460 and OMAP4470 devices have the capability to generate
alert temperature. Thus, whenever a T_ALERT IRQ is served,
the ti-bandgap will call .report_temperature to notify the
thermal framework about thermal zone update request.

This patch allows OMAP4460 and OMAP4470 devices to notify
the thermal framework about T_ALERT events.

Signed-off-by: Eduardo Valentin <eduardo.valentin@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>