tools: zynqmpimage: round up partition size

tools: zynqmpimage: round up partition size

The FSBL copies "Total Partition Word Length" * 4 bytes from the boot.bin,
which implies that the partition size is 4 byte aligned. When writing the
partition, mkimage calculates "Total Partition Word Length" by dividing
the size by 4. This implicitly cuts unaligned bytes at the end of the
added binary.

Instead of rounding down, the size must be round up to 4 bytes and the
binary padded accordingly.

Signed-off-by: Michael Tretter <m.tretter@pengutronix.de>
Reviewed-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>