bootimg: remove previous FATIMG before creating a new one
Since version 3.0.0 of dosfstools, mkdosfs opens the to-be-filesystem
file with O_EXCL. Since the filesystem is also opened with O_CREAT,
the -C option of mkdosfs can only succeed if FATIMG does not exists.
Thus, delete any previous FATIMG file. The file can be safely deleted
as we are inside build_fat_img because we want to create an new
FATIMG.
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> Signed-off-by: Ross Burton <ross.burton@intel.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
