drivers/net: include <module.h> for modular stmmac_platform code

drivers/net: include <module.h> for modular stmmac_platform code

This file is built off of a tristate Kconfig option and also contains
modular function calls so it should explicitly include module.h to
avoid compile breakage during header shuffles done in the future.

Cc: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Cc: netdev@vger.kernel.org
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>