rtc: mpfs: Use devm_clk_get_enabled() helper

The devm_clk_get_enabled() helper:
   - calls devm_clk_get()
   - calls clk_prepare_enable() and registers what is needed in order to
     call clk_disable_unprepare() when needed, as a managed resource.

This simplifies the code, the error handling paths and avoid the need of
a dedicated function used with devm_add_action_or_reset().

That said, mpfs_rtc_init_clk() is the same as devm_clk_get_enabled(), so
use this function directly instead.

This also fixes an (unlikely) unchecked devm_add_action_or_reset() error.

Based on my test with allyesconfig, this reduces the .o size from:
   text	   data	    bss	    dec	    hex	filename
   5330	   2208	      0	   7538	   1d72	drivers/rtc/rtc-mpfs.o
down to:
   5074	   2208	      0	   7282	   1c72	drivers/rtc/rtc-mpfs.o
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/e55c959f2821a2c367a4c5de529a638b1cc6b8cd.1661329086.git.christophe.jaillet@wanadoo.frSigned-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

drivers/rtc/rtc-mpfs.c

@@ -193,23 +193,6 @@ static int mpfs_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 	return 0;
 }
 
-static inline struct clk *mpfs_rtc_init_clk(struct device *dev)
-{
-	struct clk *clk;
-	int ret;
-
-	clk = devm_clk_get(dev, "rtc");
-	if (IS_ERR(clk))
-		return clk;
-
-	ret = clk_prepare_enable(clk);
-	if (ret)
-		return ERR_PTR(ret);
-
-	devm_add_action_or_reset(dev, (void (*) (void *))clk_disable_unprepare, clk);
-	return clk;
-}
-
 static irqreturn_t mpfs_rtc_wakeup_irq_handler(int irq, void *dev)
 {
 	struct mpfs_rtc_dev *rtcdev = dev;
@@ -251,7 +234,7 @@ static int mpfs_rtc_probe(struct platform_device *pdev)
 	/* range is capped by alarm max, lower reg is 31:0 & upper is 10:0 */
 	rtcdev->rtc->range_max = GENMASK_ULL(42, 0);
 
-	clk = mpfs_rtc_init_clk(&pdev->dev);
+	clk = devm_clk_get_enabled(&pdev->dev, "rtc");
 	if (IS_ERR(clk))
 		return PTR_ERR(clk);