[U-Boot] pxa310 SDHC support.

[aking_jin]

Hi, marek
     I've seen on the Internet that pxa310 support SDHC up to 32GB, but 
I'm using u-boot 2014.01, It could initialize OK.

     Device: PXA MMC
     Manufacturer ID: 3
     OEM: 5344
     Name: SS08G
     Tran Speed: 26000000
     Rd Block Len: 512
     SD version 3.0
     High Capacity: Yes
     Capacity: 7.4 GiB
     Bus Width: 4-bit

     It shows time out while reading block . Is there any particular 
process should be add?
Thank you very much.