drivers/sensor: si7006: Clean up headers

Some, like stdio.h, don't belong here at all and aren't needed.

Signed-off-by: Trent Piepho <[email protected]>

Author: xyzzy42

drivers/sensor/silabs/si7006/si7006.c

@@ -5,11 +5,10 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
+#include <zephyr/device.h>
+#include <zephyr/drivers/i2c.h>
 #include <zephyr/drivers/sensor.h>
 #include <zephyr/kernel.h>
-#include <zephyr/device.h>
-#include <zephyr/init.h>
-#include <string.h>
 #include <zephyr/sys/byteorder.h>
 #include <zephyr/sys/__assert.h>
 #include <zephyr/drivers/i2c.h>