arm/128987: [patch] Fix at91_mci and use 1-bit mode.

[M. Warner Losh]

In message: <200811302259.mAUMxvNE065100 at freefall.freebsd.org>
            stas at freebsd.org writes:
: Synopsis: [patch] Fix at91_mci and use 1-bit mode.
: 
: Responsible-Changed-From-To: freebsd-arm->stas
: Responsible-Changed-By: stas
: Responsible-Changed-When: Sun Nov 30 22:59:57 UTC 2008
: Responsible-Changed-Why: 
: I'll take it.
: 
: http://www.freebsd.org/cgi/query-pr.cgi?pr=128987

This should likely be configured on a per-board basis.  4-bit data
path does help performance, and is known to work on the AT91RM9200.

Warner