mgmt: ec_host_cmd: npcx: remove the SHI enable in the init

This commit removes the SHI enable in the initialization. It can be
enabled by the application explicitly calling it when needed. The SHI
backend relies on the application layer to provide a data buffer for EC
Host Commands. If SHI is enabled before this buffer is initialized,
there is a risk that the driver may access a NULL buffer, leading to a
system panic.

Signed-off-by: Tom Chang <CHChang19@nuvoton.com>

Author: TomChang19

subsys/mgmt/ec_host_cmd/backends/ec_host_cmd_backend_shi_npcx.c

@@ -1000,8 +1000,6 @@ static int shi_npcx_init_registers(const struct device *dev)
 	IRQ_CONNECT(DT_INST_IRQN(0), DT_INST_IRQ(0, priority), shi_npcx_isr, DEVICE_DT_INST_GET(0),
 		    0);
 
-	shi_npcx_enable(dev);
-
 	return ret;
 }