regulator: cpr3-regulator: replace kzalloc with kcalloc for arrays

Use kcalloc() and devm_kcalloc() in place of kzalloc() and
devm_kzalloc() for array memory allocations.  kcalloc() performs
a sanity check to ensure that arithmetic overflow does not occur
when calculating the full size of an array.

This issue was found with checkpatch.

Change-Id: I3e65b2b296f1865c7314f3225e48c5df52f39e01
Signed-off-by: David Collins <collinsd@codeaurora.org>