tools: kwbimage: Fix generating image with multiple DATA_DELAY commands

tools: kwbimage: Fix generating image with multiple DATA_DELAY commands

Register set header consists of sequence of DATA commands followed by
exactly one DATA_DELAY command. Thus if we are generating image with
multiple DATA_DELAY commands, we need to create more register set headers.

Fix calculation of image size with multiple DATA_DELAY commands and
correctly set pointer to struct register_set_hdr_v1 when initializing new
register set header.

Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Stefan Roese <sr@denx.de>