[U-Boot] ext4 write support and big-endian machines

Hi Tom, Uma and all,

there doesn't seem to be a dedicated filesystem maintainer, but I've included the original committer for the ext4 write support.

I guess the ext4 write support does not work on big-endian machines. As far as I see, almost no fields of the ext4 structures within the write code are byteswapped. That is very unfortunate ;) If I understand the code correctly, the fields are swapped on every access individually. This means we have to go through the "ext4 write" code and look at every field which is accessed and add an appropriate le{16,32}_to_cpu() call. Puh ;)

Btw. is the kernel style le16_to_cpu preferred to __le16_to_cpu()?

-michael