net: stmmac: Move PTP and MMC base address calculation to hwif.c

PTP and MMC modules base address can depend on the GMAC version. As this
is HW specific lets move this base address calculation to hwif.c. Also,
add an entry in the HW table so that we can specify the module offset.
This can later be extended to more modules, if deemed necessary.

Signed-off-by: Jose Abreu <joabreu@synopsys.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Joao Pinto <jpinto@synopsys.com>
Cc: Vitor Soares <soares@synopsys.com>
Cc: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>