[coreboot] Unifying IO accessor macros

[Julius Werner]

>> As Patrick already said, compared to the total effort to integrate external
>> sources, the issue of argument order is insignificant. In the time you spent
>> writing this email, you could have found out how to do it with coccinelle, and
>> could have applied it to any number of sources.
>
> http://review.coreboot.org/8483

Remember that those other code bases use writel(v, a), not write32(v,
a). Just going half the way by changing the order but not the name
wouldn't be very useful I think.

FWIW I sightly prefer write32(a, v) for purely aesthetic reasons (it's
also more in line with our current setbits_le32(a, v)), but I really
don't care much as long as we make a decision at all. There's
currently ~3500 write32()s in upstream coreboot and ~2800 writel()s in
Chromium coreboot (which has more ARM code), so now the impact for
going either direction should be roughly the same.