KVM: PPC: e500: Replace kzalloc() calls by kcalloc() in two functions

* A multiplication for the size determination of a memory allocation
  indicated that an array data structure should be processed.
  Thus use the corresponding function "kcalloc".

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>

  This issue was detected also by using the Coccinelle software.

* Replace the specification of data structures 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>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>