Add correct scatter file values for STM32F4 target

[freddan80]

The emulated target platform has more SRAM and flash than what is currently stated in the scatter file.

Fixes #43743

[google-ml-butler]

Thanks for contributing to TensorFlow Lite Micro.

To keep this process moving along, we'd like to make sure that you have completed the items on this list:

• Read the contributing guidelines for TensorFlow Lite Micro
• Created a TF Lite Micro Github issue
• Linked to the issue from the PR description

We would like to have a discussion on the Github issue first to determine the best path forward, and then proceed to the PR review.

[freddan80]

@advaitjain this should make it possible to run:
make -f tensorflow/lite/micro/tools/make/Makefile TARGET=stm32f4 TAGS=cmsis-nn person_detection_benchmark