We do disable aq_ptp module build using inline
stubs when CONFIG_PTP_1588_CLOCK is not declared.

This reduces module size and removes unnecessary code.
Reported-by: NYueHaibing <yuehaibing@huawei.com>
Signed-off-by: NIgor Russkikh <igor.russkikh@aquantia.com>
Acked-by: NRichard Cochran <richardcochran@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>