build_library: Change default MINIOS partition size for some layouts

Change the MINIOS B partition to be smaller for usb or recovery images
since it will be empty.

BUG=b:186242954
TEST=run build images which uses the usb format, unpack partitions to
verify correct USB size for MINIOS-B, then cros flash
and check partition table

Change-Id: Ic0a2cd17ab2e06a75dce19038908550c44b18c12
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosutils/+/2871109
Tested-by: Vyshu Khota <vyshu@google.com>
Commit-Queue: Amin Hassani <ahassani@chromium.org>
Reviewed-by: Amin Hassani <ahassani@chromium.org>
Reviewed-by: Mike Frysinger <vapier@chromium.org>
1 file changed