I'm not sure how this was supposed to ensure padding was zero, and it
doesn't seem to work for me (GCC 15.0.1).
Fixes a NIR validation failure with dEQP-VK.glsl.bfloat16.constant.compute
and RADV.
Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Fixes: 90e1b12890 ("spirv: Add bfloat16 support to SpecConstantOp")
Reviewed-by: Georg Lehmann <dadschoorse@gmail.com>
Reviewed-by: Caio Oliveira <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/34769>