soc: npcx: update the NUM_IRQS value for npcx4

The npcx4 SoC only uses 86 NVIC IRQ numbers.
This commit updates the number from 128 to 86 to reduce the memory
usage.

Signed-off-by: Jun Lin <CHLin56@nuvoton.com>

Author: ChiHuaL

soc/nuvoton/npcx/npcx4/Kconfig.defconfig

@@ -6,7 +6,7 @@
 if SOC_SERIES_NPCX4
 
 config NUM_IRQS
-	default 128
+	default 86
 
 config CORTEX_M_SYSTICK
 	default !NPCX_ITIM_TIMER