fsl_sata: Make sata_{read,write}() comply with <part.h>

- sata_write() takes a const void as the last argument.  Fixing this
  means we also need to make ata_low_level_rw_lba{28,48} also take a
  const void.
- Both sata_{read,write} take lbaint_t for blkcnt and ulong for blknr

Signed-off-by: Tom Rini <trini@ti.com>