dmaengine: PL08x: Move LLI dumping code into separate function

This patch refactors debugging code that dumps LLI entries by moving it
into separate function, which is stubbed when VERBOSE_DEBUG is not
selected. This allows us to get rid of the ugly ifdef from the body of
pl08x_fill_llis_for_desc().

No functional change is introduced by this patch.

Signed-off-by: Tomasz Figa <tomasz.figa@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>