freedreno/ir3: fix fallout of extra assert

freedreno/ir3: fix fallout of extra assert

Fixes the following crash that happened after d6110d4d

The problem happens if we first compile a "vanilla" shader with nothing
lowered in NIR, which perform the final lowering passes on so->shader->
nir (including nir_lower_locals_to_regs()), and then later we have
compile a shader with some lowering.  The second time through we would
have already done nir_lower_locals_to_regs().

Arguably this was already a bug, just one we hadn't noticed yet.

Fixes: d6110d4d547 intel/compiler: move nir_lower_bool_to_int32 before nir_lower_locals_to_regs
Signed-off-by: Rob Clark <robdclark@gmail.com>