Move loads to beginning of BUILD files.

Change-Id: Idb918a48cfe6149f624295f6712fbf0a3a36a7ff
diff --git a/pw_preprocessor/BUILD b/pw_preprocessor/BUILD
index 206521d..be20566 100644
--- a/pw_preprocessor/BUILD
+++ b/pw_preprocessor/BUILD
@@ -12,16 +12,16 @@
 # License for the specific language governing permissions and limitations under
 # the License.
 
-package(default_visibility = ["//visibility:public"])
-
-licenses(["notice"])  # Apache License 2.0
-
 load(
     "//pw_build:pigweed.bzl",
     "pw_cc_library",
     "pw_cc_test",
 )
 
+package(default_visibility = ["//visibility:public"])
+
+licenses(["notice"])  # Apache License 2.0
+
 pw_cc_library(
     name = "pw_preprocessor",
     hdrs = glob(["public/pw_preprocessor/*.h"]),