[STM32H735]: Can't access external memory

[c-grant]

Issue is similar to issue #1158, except it is in relation the the externally mapped memory busses

Programmer/board type: [STLINK V3 on STM32H735-DK]
Operating system an version: [Windows 10 19042.1083]
stlink tools version and/or git commit hash: [1.7.0]
stlink commandline tool name: [st-util]
Target chip (and board, if applicable): [STM32H735 on STM32H735-DK]

When tryin to read OSPI2 on the STM32H735-DK the memory could not be read.

Investigating the gdb-server.c these regions were also missing.

Pull has been created and HyperRAM on OSPI2 can now be read

[c-grant]

Fixed by #1197