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>