board/stmicroelectronics/stm32f469-disco: remove OpenOCD patches

board/stmicroelectronics/stm32f469-disco: remove OpenOCD patches

Since the bump of OpenOCD from 0.9.0 to 0.10.0 in commit
3b6c74d708252a32fe172be944951396d419ba88, stm32f469_disco_defconfig
fails to build:

 - 0001-add-config.patch was merged in upstream OpenOCD (commit
   26045588f462476cee356d15a24944d6c26befb4).

 - 0002-flash-nor.patch was merged in upstream OpenOCD (commit
   3e219648c80a27f0519003f3b088cbb846e255d8)

Therefore, this commit removes the two patches that are no longer
necessary.

Fixes:

  https://gitlab.com/buildroot.org/buildroot/builds/15762279

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>