cmake: mcuboot: set align to 1 for overwrite only mode

Set align to 1 for CONFIG_MCUBOOT_IMGTOOL_OVERWRITE_ONLY,
used by non-swap update modes.
Fix imgtool error message for device with write size > 32B.

Signed-off-by: Andrej Butok <andrey.butok@nxp.com>
1 file changed