serial: mxc: Support bulk enabling clocks

Depending on the platform, there may be multiple clock sources
required to enable a UART. Use the bulk functions to get and
enable the clocks when the UART probes. This can facilitate
the removal of functions to manually enable the clock.

This is made dependent on CLK_CCF which is used on imx6q,
imx8m[mnqp], several imxrt, imx9. If/when the UART clock
registration is done for older boards, this limitation
could be updated.

Signed-off-by: Adam Ford <[e-mail]>
Reviewed-by: Peng Fan <[e-mail]>

drivers/serial/serial_mxc.c

···
  * (c) 2007 Sascha Hauer <[e-mail]>
  */
 
+#include <clk.h>
 #include <dm.h>
 #include <errno.h>
 #include <watchdog.h>
···
 static int mxc_serial_probe(struct udevice *dev)
 {
 	struct mxc_serial_plat *plat = dev_get_plat(dev);
+#if CONFIG_IS_ENABLED(CLK_CCF)
+	int ret;
 
+	ret = clk_get_bulk(dev, &plat->clks);
+	if (ret)
+		return ret;
+
+	ret = clk_enable_bulk(&plat->clks);
+	if (ret)
+		return ret;
+#endif
 	_mxc_serial_init(plat->reg, plat->use_dte);
 
 	return 0;

include/dm/platform_data/serial_mxc.h

···
 /* Information about a serial port */
 struct mxc_serial_plat {
 	struct mxc_uart *reg;  /* address of registers in physical memory */
+#if CONFIG_IS_ENABLED(CLK_CCF)
+	struct clk_bulk clks;
+#endif
 	bool use_dte;
 };