tests: drivers: spi: spi_loopback: update testcase file

add stm32n6570_dk in yaml file for CI test integration
purpose.

Signed-off-by: Fabrice DJIATSA <[email protected]>

Author: djiatsaf-st

tests/drivers/spi/spi_loopback/testcase.yaml

@@ -80,6 +80,7 @@ tests:
       - nucleo_h745zi_q/stm32h745xx/m4
       - nucleo_h745zi_q/stm32h745xx/m7
       - stm32h573i_dk
+      - stm32n6570_dk/stm32n657xx/sb
     integration_platforms:
       - nucleo_g474re
   drivers.spi.stm32_spi_dma_dt_nocache_mem.loopback:
@@ -137,6 +138,7 @@ tests:
       - nucleo_wl55jc
       - stm32f3_disco
       - stm32h573i_dk
+      - stm32n6570_dk/stm32n657xx/sb
     integration_platforms:
       - stm32h573i_dk
   drivers.spi.gd32_spi_interrupt.loopback: