Remove listAvailableGpios.

This is not useful as we don't expect users to take runtime decisions
based on this.

Bug: 27836221
Bug: 27836293
Change-Id: Ieef02af25b222ec52cfe7f35d91f31707d438267
diff --git a/include/peripheralmanager/peripheral_manager_client.h b/include/peripheralmanager/peripheral_manager_client.h
index 8941a4c..5fdc5ff 100644
--- a/include/peripheralmanager/peripheral_manager_client.h
+++ b/include/peripheralmanager/peripheral_manager_client.h
@@ -41,15 +41,6 @@
 char** BPeripheralManagerClient_listGpio(const BPeripheralManagerClient* client,
                                          int* num_gpio);
 
-/// Returns the list of available GPIOs.
-/// The list must be freed by the caller.
-/// @param client Pointer to the BPeripheralManagerClient struct.
-/// @param num_gpio Output pointer to the number of element in the list.
-/// @return The list of buses.
-char** BPeripheralManagerClient_listAvailableGpio(
-    const BPeripheralManagerClient* client,
-    int* num_gpio);
-
 /// Opens a GPIO and takes ownership of it.
 /// @param client Pointer to the BPeripheralManagerClient struct.
 /// @param name Name of the GPIO.