staging: omap-thermal: add OMAP4 data structures

This patch adds the data structures needed for proper registration
of OMAP4 chips. This patch includes definitions for these chip versions:
. OMAP4430
. OMAP4460
. OMAP4470

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