gallivm: Remove NULL check of pointer that can't be NULL.

info cannot be NULL at the call to debug_printf. emit_instruction
dereferences info, so at debug_printf it is either not NULL or the
program has already crashed.

src/gallium/auxiliary/gallivm/lp_bld_tgsi_soa.c

@@ -1812,7 +1812,7 @@ lp_build_tgsi_soa(LLVMBuilderRef builder,
             const struct tgsi_opcode_info *info = tgsi_get_opcode_info(opcode);
             if (!emit_instruction( &bld, &parse.FullToken.FullInstruction, info ))
                _debug_printf("warning: failed to translate tgsi opcode %s to LLVM\n",
-                             info ? info->mnemonic : "<invalid>");
+                             info->mnemonic);
          }
 
          break;