stm32/boards/STM32F769DISC: Fix length of FLASH_APP section.
Fixes issue
MEMORY
{
- FLASH_APP (rx) : ORIGIN = 0x08020000, LENGTH = 2016K /* sectors 1-11 3x32K 1*128K 7*256K */
+ FLASH_APP (rx) : ORIGIN = 0x08020000, LENGTH = 1920K /* sectors 4-11 1*128K 7*256K */
FLASH_QSPI (rx) : ORIGIN = 0x90000000, LENGTH = 64M /* external QSPI flash in XIP mode */
DTCM (xrw) : ORIGIN = 0x20000000, LENGTH = 128K /* Used for storage cache */
RAM (xrw) : ORIGIN = 0x20020000, LENGTH = 384K /* SRAM1 = 368K, SRAM2 = 16K */
