ARM: OMAP2+: Add machine entry for dra72x devices

The only difference from the dra74x devices is the missing .smp entry.

Signed-off-by: Rajendra Nayak <rnayak@ti.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Tony Lindgren <tony@atomide.com>