bsp-an552: Amend files copied from TF-M

The following changes are required for AN552 to work with
Total Solutions:
* Re-configure the flash layout to take advantage of the
QSPI flash
* Uses QSPI for FLASH0 rather than SRAM
* Adds in defintions for DDR4 MPC
* Increase the heap and stack sizes
* Change the MPC settings
* Rename the Ethos U IRQ handler

QSPI is used for the flash rather than SRAM because
SRAM does not have enough memory to hold the image
for Total Solutions Keyword and Speech examples.

Signed-off-by: Jack Styles <jack.styles@arm.com>