net: stmmac: Get rid of custom STMMAC_DEVICE() macro

Since PCI core provides a generic PCI_DEVICE_DATA() macro,
replace STMMAC_DEVICE() with former one.

No functional change intended.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>