fs: sdfat: initial import from cryptomilk

From https://github.com/cryptomilk/kernel-sdfat @ 2ec9cdae9c794c33b4adf4fcdf97758b0a5dd4b3
  - fs: sdfat: __sdfat_submit_bio_write() should always submit a WRITE

Change-Id: I8deb764a778f463c8902cd1397d3ca1cf89786a7
Signed-off-by: Alexander Martinz <amartinz@shiftphones.com>
31 files changed