[PATCH 7/8] mmc: sdhci-of-aspeed: Remove timing phase

[Cool Lee]

> > The timing phase is no more needed since the auto tuning is applied.
> >
> 
> I feel this is unwise: we're now ignoring constraints set in the devicetree.
> Auto-tuning is fine, but I think that should be a feature that new platforms can
> exploit by default. Older platforms that do specify the phase values via the
> devicetree can be converted at the leisure of their maintainers (by removing
> the phase properties).
> 
> Support needs to remain in the driver until there are no (aspeed-based)
> devicetrees specifying the phases.
The timing phase only works on AST2600 or newer platform which has added a delay cell in the RTL.
The older platform AST2500, AST2400 doesn't support the timing phase.
It supposed no effect on older platform. 
The old manner that a static timing value customized from devicetree is inconvenient because customer needs to check waveform associated with each delay taps. Once the emmc parts changed, a fixed timing value may not work. That's why auto tune here instead of a static value.

> 
> Andrew