drivers: peci: npcx: use portable IRQ pending API

Replace direct NVIC_SetPendingIRQ()/NVIC_ClearPendingIRQ() calls with
k_irq_set_pending()/k_irq_clear_pending(), dropping the dependency on
cmsis_core.h where nothing else needed it. These platforms are
plain-NVIC Cortex-M, so the pending-state capabilities are always
available where this code builds.

Assisted-by: Claude:claude-opus-5
Signed-off-by: Anas Nashif <anas.nashif@intel.com>

Author: nashif

drivers/peci/peci_npcx.c

@@ -124,7 +124,7 @@ static int peci_npcx_enable(const struct device *dev)
 
 	reg->PECI_CTL_STS = BIT(NPCX_PECI_CTL_STS_DONE) | BIT(NPCX_PECI_CTL_STS_CRC_ERR) |
 			    BIT(NPCX_PECI_CTL_STS_ABRT_ERR);
-	NVIC_ClearPendingIRQ(DT_INST_IRQN(0));
+	k_irq_clear_pending(DT_INST_IRQN(0));
 	irq_enable(DT_INST_IRQN(0));
 
 	k_sem_give(&data->lock);