driver core: platform: removed unneeded variable from __platform_driver_probe()

driver core: platform: removed unneeded variable from __platform_driver_probe()

In the reworking of the function __platform_driver_probe() over the
years, it turns out that the variable 'code' does not actually do
anything or mean anything anymore and can be removed to simplify the
logic when trying to read and understand what this function is actually
doing.

Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Link: https://lore.kernel.org/r/20230131082459.301603-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>