radeonsi: Set LS-HS vertex stride to zero when there are no LS outputs.
In both cases, the driver won't need to allocate any LDS for LS outputs / TCS inputs, because:
- For monolithic shaders:
The patch0 offset will be constant zero. - For part shaders:
The shader will calculate that the patch0 offset is zero.
With this change, we can remove the extra code path of no_inputs_in_lds
from the HS output lowering.