fix mounting fat12/fat16/fat32/fat

README.disk_layout states that fat/fat12/fat16/fat32 are legal fs_format
values.
while fs_create has custom handling for each specific fat fs type and
calls mkfs.vfat, fs_mount has no special handling and trys to mount them
using the fs_format value as fs type which fails. It needs to use type vfat.

BUG=none
TEST=run build_image with a disk_layout.json using fat32 for the efi
partition

Change-Id: I34a9f119e66842792f8c94d23425971639c760c1
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosutils/+/3168331
Commit-Queue: Alex Klein <saklein@chromium.org>
Tested-by: Carsten Schiemann <cschiemann@google.com>
Auto-Submit: Carsten Schiemann <cschiemann@google.com>
Reviewed-by: Alex Klein <saklein@chromium.org>
1 file changed