[mlir][bazel] Remove defines of obsolete MLIR_GPU_TO_CUBIN_PASS_ENABLE. (#83006)

This macro is obsolete since the landing of #82486 but was forgotten to
be removed from the BUILD files.

Author: ingomueller-net

utils/bazel/llvm-project-overlay/mlir/BUILD.bazel

@@ -5508,7 +5508,6 @@ cc_library(
     ),
     hdrs = glob(["include/mlir/Dialect/GPU/Transforms/*.h"]),
     includes = ["include"],
-    local_defines = if_cuda_available(["MLIR_GPU_TO_CUBIN_PASS_ENABLE"]),
     deps = [
         ":AffineDialect",
         ":AffineUtils",

utils/bazel/llvm-project-overlay/mlir/test/BUILD.bazel

@@ -4,7 +4,6 @@
 
 load("@bazel_skylib//rules:expand_template.bzl", "expand_template")
 load("//llvm:lit_test.bzl", "package_path")
-load("//mlir:build_defs.bzl", "if_cuda_available")
 load("//mlir:tblgen.bzl", "gentbl_cc_library", "td_library")
 
 package(
@@ -663,9 +662,6 @@ cc_library(
 cc_library(
     name = "TestGPU",
     srcs = glob(["lib/Dialect/GPU/*.cpp"]),
-    defines = if_cuda_available([
-        "MLIR_GPU_TO_CUBIN_PASS_ENABLE",
-    ]),
     includes = ["lib/Dialect/Test"],
     deps = [
         "//llvm:NVPTXCodeGen",