Simplify probe error path and remove callback by using device-managed
functions.

rtl_disable_msi isn't needed any longer because the release callback
of pcim_enable_device does this implicitely.
Signed-off-by: NHeiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>