ste_dma40: Replace four kzalloc() calls by kcalloc() in d40_hw_detect_init()

* The script "checkpatch.pl" can point information out like the following.

  WARNING: Prefer kcalloc over kzalloc with multiply

  Thus fix the affected source code places.

* Replace the specification of data types by pointer dereferences
  to make the corresponding size determination a bit safer according to
  the Linux coding style convention.

Signed-off-by: Markus Elfring <elfring@users.sourceforge.net>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>