ARM: OMAP3+: am33xx id: Add new am33xx specific function to check dev_feature

Layout of DEV_FEATURE register (offset = 0x604) is different
between TI81xx and AM33xx device, so create separate function
which will check for features available on specific AM33xx SoC
and set the flags accordingly.

Signed-off-by: Vaibhav Hiremath <hvaibhav@ti.com>
Reviewed-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>