DMA: PL08x: select LLI bus only once per LLI setup

Avoid re-selecting the LLI bus each time we create an LLI.  Move it out
of the LLI setup loops.

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>