build: Quote asm arg to allow bld w/spaces in path
build: Quote asm arg to allow bld w/spaces in path

Put quotes around an assembler argument in CMake file
to reenable building this repo on a path that contains
space characters.

Change-Id: Ic89737f4611161ec0bf4fe53ea59d9e2cd553d9b

KhronosGroup/Vulkan-LoaderAndValidationLayers,KhronosGroup/Vulkan-LoaderAndValidationLayers,KhronosGroup/Vulkan-LoaderAndValidationLayers,KhronosGroup/Vulkan-LoaderAndValidationLayers