iio: light: stk3310: Update includes to match IWYU

iio: light: stk3310: Update includes to match IWYU

Clean up the included headers in stk3310.c according to the
Include-What-You-Use (IWYU) tool. Remove the generic <linux/kernel.h>
header and add explicit dependencies to improve compilation accuracy.

Co-developed-by: Felipe Khoury Dayoub <felipedayoub@usp.br>
Signed-off-by: Felipe Khoury Dayoub <felipedayoub@usp.br>
Signed-off-by: Rafael G. Dias <rafael.guimaraes.dias@usp.br>
Reviewed-by: Joshua Crofts <joshua.crofts1@gmail.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>