[bazel] Split TransformDialect into a header-only lib in prep for PR85221

This lets users use TensorDialect without depending on all dialects
transitively. 513cdb8 forces that
otherwise.

Author: d0k

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

@@ -7382,7 +7382,7 @@ cc_library(
         ":Support",
         ":TensorOpsIncGen",
         ":TilingInterface",
-        ":TransformDialect",
+        ":TransformDialectInterfaces",
         ":ValueBoundsOpInterface",
         ":ViewLikeInterface",
         "//llvm:Support",
@@ -12064,6 +12064,24 @@ gentbl_cc_library(
     deps = [":TransformDialectTdFiles"],
 )
 
+cc_library(
+    name = "TransformDialectInterfaces",
+    # FIXME: Change this once https://github.com/llvm/llvm-project/pull/85221 lands
+    hdrs = glob(["include/mlir/Dialect/Transform/IR/*.h"]),
+    deps = [
+        ":CastInterfaces",
+        ":IR",
+        ":Rewrite",
+        ":SideEffectInterfaces",
+        ":Support",
+        ":TransformDialectInterfacesIncGen",
+        ":TransformDialectUtils",
+        ":TransformTypesIncGen",
+        ":Transforms",
+        "//llvm:Support",
+    ],
+)
+
 cc_library(
     name = "TransformDialect",
     srcs = glob(["lib/Dialect/Transform/IR/*.cpp"]),