Revert "[media] omap3isp: Replace cpu_is_omap3630() with ISP revision check"

Reverted, as requested by Laurent:

I don't consider it as being ready yet, as Sakari pointed out we need
to investigate whether the right fix shouldn't be at the OMAP3 clocks
level instead.

This reverts commit 947c4808

.

Requested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Tony Lindgren <tony@atomide.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>