[RFT] au1xmmc: remove board-specific code

[Manuel Lauss <mano@roarinelk.homelinux.net>]

Hello,

I received a new Au1200 based toy on which the current driver-implemented
SD card-detect scheme doesn't work.  However since this toy does have a 
dedicated SD carddetect IRQ and card status bits, I took the opportunity
to get rid of the DB1200 specific parts in the driver and added callbacks
for platform/board-specific carddetect and voltage setting methods.

What I need is feedback from testers with access to db1200/pb1200 boards:
The patch below (+ boardstuff) works on my board but I'm not sure if
I got the carddetect poll timer for the db1200 right.

Please test and comment!

Thanks!
        Manuel Lauss

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