arm: omap3: am35x: Don't mark missing features as present

The Chip Identification register on the am35x family of SoCs
has bits 12, 7:5, and 3:2 marked as reserved and are read as
zeroes.  Unfortunately, on other omap SoCs, a 0 bit means a
feature is "Full Use" so the OMAP3_CHECK_FEATURE() macro
called by omap3_check_features() will incorrectly interpret
those zeroes to mean that a feature is present even though it
isn't.  To fix that, the feature bits that are incorrectly
set (namely, OMAP3_HAS_IVA and OMAP3_HAS_ISP) need to be
cleared after all of the calls to OMAP3_CHECK_FEATURE() in
omap3_check_features() are made.

Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
[khilman@ti.com: use soc_is_am35xx() instead of cpu_is_am35xx()]
Signed-off-by: Kevin Hilman <khilman@ti.com>