target/stm32h7x: Fix documentation of reset_config

target/stm32h7x: Fix documentation of reset_config

The stm32h7x.cfg does not specify connect_assert_srst or
connect_deassert_srst in its reset_config. The comment claims that it
will therefore connect in reset. However, per the manual, the default
configuration is actually connect_deassert_srst, not
connect_assert_srst. In actual fact, connect_assert_srst does not work
on the STM32H7 because, while SRST is asserted, everything on the AXI
bus is inaccessible. The CPU core is accessible, but since the
examine-end event handler also pokes at the DBGMCU peripheral, that will
fail in connect_assert_srst mode. So using connect_deassert_srst is
appropriate, so fix the comment accordingly.

Change-Id: If3e32e871fb19cc61183bdf911b7c5efd80b62e2
Signed-off-by: Christopher Head <chead@zaber.com>
Reviewed-on: http://openocd.zylin.com/4741
Tested-by: jenkins
Reviewed-by: Tomas Vanek <vanekt@fbl.cz>