net: ieee802154: at86rf230: Switch to use hrtimer_setup()

hrtimer_setup() takes the callback function pointer as argument and
initializes the timer completely.

Replace hrtimer_init() and the open coded initialization of
hrtimer::function with the new setup mechanism.

Signed-off-by: Nam Cao <[e-mail]>
Signed-off-by: Thomas Gleixner <[e-mail]>
Link: https://lore.kernel.org/all/[e-mail]

drivers/net/ieee802154/at86rf230.c

···
 	state->trx.tx_buf = state->buf;
 	state->trx.rx_buf = state->buf;
 	spi_message_add_tail(&state->trx, &state->msg);
-	hrtimer_init(&state->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
-	state->timer.function = at86rf230_async_state_timer;
+	hrtimer_setup(&state->timer, at86rf230_async_state_timer, CLOCK_MONOTONIC,
+		      HRTIMER_MODE_REL);
 }
 
 static irqreturn_t at86rf230_isr(int irq, void *data)