graphics/vulkan-headers: unbreak 32-bit consumers after 4868165d658c

In file included from /usr/local/include/vulkan/vulkan.hpp:8864:
/usr/local/include/vulkan/vulkan_structs.hpp:1241:90: error: invalid operands to binary expression ('const vk::AccelerationStructureKHR' and 'const vk::AccelerationStructureKHR')
1241 | return ( sType == rhs.sType ) && ( pNext == rhs.pNext ) && ( accelerationStructure == rhs.accelerationStructure ) &&

|                                                                    ~~~~~~~~~~~~~~~~~~~~~ ^  ~~~~~~~~~~~~~~~~~~~~~~~~~

Reported by: pkg-fallout (benchmarks/vkmark, emulators/flycast)