clk: imx: Drop inclusion of unused header <soc/imx/timer.h>

The clk drivers use none of the symbols defined in <soc/imx/timer.h>.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20230328100531.879485-2-u.kleine-koenig@pengutronix.de