uboot-phytec

sandbox: Use md5sum and fatwrite to enable testing of fs commands

Enable md5sum to obtain the MD5 of the read and written files to check
their contents for validity.
Use map_sysmem() to map buffer in a sandbox environment.

Signed-off-by: Suriyan Ramasami <suriyan.r@gmail.com>

Acked-by: Simon Glass <sjg@chromium.org>