[PATCH V3 4/4] mmc: sdhci-esdhc: enable esdhc on imx53

[Eric Miao]

>> Hmm, to me, just using cpu_is_mx53() is more readable than introducing
>> another layer of flags/quirks.
> Hi Wolfram:
> I discussed it with Richard Zhao before sending out these V3 patches.
> As we know that there is not only mx53 has this issue, maybe some following SOCs have this issue too.
> So we make a decision that we introduce another flags/quirks to declare it for all those SOCs that required this
> mechanism in the end.

I agree with Richard here that a flag/quirk will be more generic than
cpu_is_*(). Otherwise we may end up one day growing a big list of
these cpu_is_*().

One other point to consider is the SoC stepping, as this might be
fixed in later steppings, and keeping cpu_is_mx53() or
cpu_is_mx53_stepping_b2_or_above() doesn't look very good in
the driver code itself.