[sdk] Add fuchsia.io to the sdk BUILD.gn instead of transative include.

Bug: 36541
Change-Id: Icf838ef5f1753cc26c5896d2749cfdcec9da9e58
diff --git a/sdk/BUILD.gn b/sdk/BUILD.gn
index 1a90b33..c849d72 100644
--- a/sdk/BUILD.gn
+++ b/sdk/BUILD.gn
@@ -141,6 +141,7 @@
     "//zircon/system/fidl/fuchsia-hardware-goldfish-address-space:fuchsia-hardware-goldfish-address-space_sdk($fidl_toolchain)",
     "//zircon/system/fidl/fuchsia-hardware-goldfish-control:fuchsia-hardware-goldfish-control_sdk($fidl_toolchain)",
     "//zircon/system/fidl/fuchsia-hardware-goldfish-pipe:fuchsia-hardware-goldfish-pipe_sdk($fidl_toolchain)",
+    "//zircon/system/fidl/fuchsia-io:fuchsia-io_sdk($fidl_toolchain)",
     "//zircon/system/fidl/fuchsia-logger:fuchsia-logger_sdk($fidl_toolchain)",
     "//zircon/system/fidl/fuchsia-mem:fuchsia-mem_sdk($fidl_toolchain)",
     "//zircon/system/fidl/fuchsia-posix-socket:fuchsia-posix-socket_sdk($fidl_toolchain)",