tools: kwbimage: Fix generation of SATA, SDIO and PCIe images

SATA and SDIO images must be aligned to sector size (which in most cases
is 512 bytes) and Source Address in main header is stored in number of
sectors from the beginning of the drive. SATA image must be stored at
sector 1 and SDIO image at sector 0. Source Address for PCIe image is
not used and must be set to 0xFFFFFFFF.

Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Stefan Roese <sr@denx.de>
Reviewed-by: Chris Packham <judge.packham@gmail.com>
Tested-by: Chris Packham <judge.packham@gmail.com>