ARM: PL08x: make pl08x_fill_lli_for_desc() return void

We don't need pl08x_fill_lli_for_desc() to return num_llis + 1 as
we know that's what it always does.  We can just pass in num_llis
and use post-increment in the caller.

This makes the code slightly easier to read.

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>