layers: Fix param checker struct array handling

Fix parameter validation issue with arrays of structs, where only
the first item in the array was processed.  Validation messages
for arrays of structs will currently print the array variable name
with the letter 'i' as the array index instead of the actual index
number, producing a value like 'pCreateInfos[i]'.  This will be
fixed by a future update.

Change-Id: I2cb773c23c6515a20ac8cb066e7cc61028e569f8