soc: same70: enable instruction cache on sam_e70

The Cortex-M7 CPU included in the SAM e70 SoCs has an instruction cache
that significantly boost the performances. Enable it during the SoC
initialization.

Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>

soc/arm/atmel_sam/same70/soc.c

@@ -227,6 +227,8 @@ static int atmel_same70_init(struct device *arg)
 
 	key = irq_lock();
 
+	SCB_EnableICache();
+
 	/* Clear all faults */
 	_ClearFaults();