OMAP7XX: Update core omap1 files to use omap7xx.h

This patch is part of a series which removes references to omap730 in code
which is shared with omap850, replacing them with references to omap7xx.

Signed-off-by: Alistair Buxton <a.j.buxton@gmail.com>
Reviewed-by: Zebediah C. McClure <zmc@lurian.net>