Allow JTAG connection while in reset
Allow JTAG connection while in reset

Add OpenOCD command 'connect_assert_srst' to allow JTAG connection while
the chip is being held in reset. This allows the chip to be reprogrammed
even if the application has remapped them for other uses.

Refer to:
https://electronics.stackexchange.com/questions/61407/overwrote-stm32f4-st-link-pins

oliverlee/phobos,oliverlee/phobos,oliverlee/phobos,oliverlee/phobos