fix: call effective ETH scheduler only from Timer callback
Restrict effective ETH scheduler to Timer callback only.
This is to avoid any race condition on ETH scheduler,
which could previously be called from timer ISR,
as well as DHCP or UDP driver parts.
Any direct request for ETH scheduler (direct call to stm32_eth_scheduler())
will generate a Timer Update Event to force a call to timer callback
fix: call effective ETH scheduler only from Timer callback
Restrict effective ETH scheduler to Timer callback only. This is to avoid any race condition on ETH scheduler, which could previously be called from timer ISR, as well as DHCP or UDP driver parts. Any direct request for ETH scheduler (direct call to stm32_eth_scheduler()) will generate a Timer Update Event to force a call to timer callback
Fixes #45