zynq: Remove zynq_cseflash board config

There is no updates on this config since from last
couple of releases, hence removed it.

Signed-off-by: Jagannadha Sutradharudu Teki <jaganna@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
sf: Compute the dual parallel write chunk_len based on offset

chunk_len in should be interms of page_size, as page_size
is double in dual parallel chunk_len must be computed based
on the offset not with write_addr.

Signed-off-by: Jagannadha Sutradharudu Teki <jaganna@xilinx.com>
Signed-off-by: Michal Simek <michal.simek@xilinx.com>