stm32f1.c: On a read protected device, deny any other option action than erase.

Otherwise the first option action triggers an error, inhibiting further option
actions.
stm32f1: Fix handling of option byte write. Write needs to happend on erased option bytes.
stlink: Give the NRST check more time as otherwise some L1 discovery board stayed in the bootloader.
STM32F4: Recognize F401.
STM32F4: Add handling of second bank and dual boot devices.