layers: Add missing compute stage sType check
layers: Add missing compute stage sType check

The parameter_validation code generator was only generating sType checks
for pointers to structures.  There is one case where a non-pointer struct
parameter needs to be validated: the VkComputePipelineCreateInfo::stage
member of the vkCreateComputePipelines pCreateInfos parameter.  The code
generator has been updated to handle this case.

Change-Id: I1e695fcc875574eae94912ceb6338428d7ed8b49

KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools,KhronosGroup/Vulkan-Tools