stmmac: Move the STMicroelectronics driver

Move the STMicroelectronics driver into driver/net/ethernet/stmicro/ and
make the necessary Kconfig and Makefile changes.

CC: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
27 files changed