Patch from Richard Purdie

PXA Corgi - Bugfix + Cleanups:
* Make sure the MMC timer init is called *before* enabling the
  interrupt (thanks Nicholas for pointing this out).
* Add externs for the exported ssp functions
* Finish commenting Corgi specific GPIOs
[Applies after 2428/1]

Signed-off-by: Richard Purdie
Signed-off-by: Russell King