thermal: imx8mm: Fix build warning of incorrect argument type

Fix below sparse warning:

drivers/thermal/imx8mm_thermal.c:82:36: sparse: sparse: incorrect type in argument 2 (different address spaces), expected unsigned long const volatile *addr
drivers/thermal/imx8mm_thermal.c:82:36: sparse: expected unsigned long const volatile *addr

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/1584973156-25734-1-git-send-email-Anson.Huang@nxp.com

drivers/thermal/imx8mm_thermal.c

@@ -75,15 +75,14 @@ static int imx8mp_tmu_get_temp(void *data, int *temp)
 {
 	struct tmu_sensor *sensor = data;
 	struct imx8mm_tmu *tmu = sensor->priv;
+	unsigned long val;
 	bool ready;
-	u32 val;
 
-	ready = test_bit(probe_status_offset(sensor->hw_id),
-			 tmu->base + TRITSR);
+	val = readl_relaxed(tmu->base + TRITSR);
+	ready = test_bit(probe_status_offset(sensor->hw_id), &val);
 	if (!ready)
 		return -EAGAIN;
 
-	val = readl_relaxed(tmu->base + TRITSR);
 	val = sensor->hw_id ? FIELD_GET(TRITSR_TEMP1_VAL_MASK, val) :
 	      FIELD_GET(TRITSR_TEMP0_VAL_MASK, val);
 	if (val & SIGN_BIT) /* negative */