layers: Remove more AllocateDescriptorSets noise
layers: Remove more AllocateDescriptorSets noise

Can argue about whether this stuff at INFO level is worthwhile...
Replace the comments with a clearer set of comments.

Signed-off-by: Chris Forbes <c3279c50043e18e9442c1ae071cafa0e7a4ca967@google.com>

Radamanthe/VulkanSamples,Radamanthe/VulkanSamples,Radamanthe/VulkanSamples,Radamanthe/VulkanSamples,Radamanthe/VulkanSamples,Radamanthe/VulkanSamples