Add load for cc_import

Author: dzbarsky

toolchain/BUILD.toolchain.tpl

@@ -15,7 +15,7 @@
 package(default_visibility = ["//visibility:public"])
 
 load("@bazel_skylib//rules:native_binary.bzl", "native_binary")
-load("@rules_cc//cc:defs.bzl", "cc_toolchain", "cc_toolchain_suite")
+load("@rules_cc//cc:defs.bzl", "cc_import", "cc_toolchain", "cc_toolchain_suite")
 load("@toolchains_llvm//toolchain/internal:system_module_map.bzl", "system_module_map")
 load("%{cc_toolchain_config_bzl}", "cc_toolchain_config")