layers: Fixup MappedMemRanges call ordering
layers: Fixup MappedMemRanges call ordering

Moved validation out of API calls.

Change-Id: I95f3b24d69d469ea98b7c955bbab56c9b47ad487

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