rtc: k3: Use devm_clk_get_enabled() helper

rtc: k3: 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().

Based on my test with allyesconfig, this reduces the .o size from:
   text	   data	    bss	    dec	    hex	filename
   12843	   4804	     64	  17711	   452f	drivers/rtc/rtc-ti-k3.o
down to:
   12523	   4804	     64	  17391	   43ef	drivers/rtc/rtc-ti-k3.o

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/601288834ab71c0fddde7eedd8cdb8001254ed7e.1661329498.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>