aco: enable value numbering of s_buffer_load_*

fossil-db (Navi):
Totals from 33 (0.03% of 114665) affected shaders:
SGPRs: 2176 -> 2152 (-1.10%)
VGPRs: 1572 -> 1564 (-0.51%)
CodeSize: 115988 -> 115472 (-0.44%)
Instrs: 21459 -> 21385 (-0.34%)

Signed-off-by: Rhys Perry <pendingchaos02@gmail.com>
Reviewed-by: Daniel Schürmann <daniel@schuermann.dev>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4905>

src/amd/compiler/aco_opt_value_numbering.cpp

@@ -224,8 +224,6 @@ struct InstrPred {
             return aK->imm == bK->imm;
          }
          case Format::SMEM: {
-            if (!a->operands.empty() && a->operands[0].bytes() == 16)
-               return false;
             SMEM_instruction* aS = static_cast<SMEM_instruction*>(a);
             SMEM_instruction* bS = static_cast<SMEM_instruction*>(b);
             /* isel shouldn't be creating situations where this assertion fails */