r8169: consolidate disabling ASPM before EPHY access

Now that rtl_hw_aspm_clkreq_enable() is a no-op for chip versions < 32,
we can consolidate disabling ASPM before EPHY access in rtl_hw_start().

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>