i2c/isp1301_omap: Build fixes

Build fixes for isp1301_omap; no behavior changes:

  - fix incorrect probe() signature (it changed many months ago)
  - provide missing functions on H3 and H4 boards
  - "sparse" fixes (static, NULL-vs-0)

The H3 build bits subset some of the stuff that was previously in
the OMAP tree but never went to mainline.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>