base/platform: Remove code duplication

Failure path of platform_device_add was almost the same as
platform_device_del. Refactor same code in a function.

Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>