ARM: PL08x: move default cctl into txd structure

Rather than modifying platform data while preparing a transfer, copy
the cctl value into the txd structure and modify the value there.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>