tty: serial: meson: Use devm_clk_get_enabled() helper

tty: serial: meson: 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, meson_uart_probe_clock() is now more or less 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
   16350	   5016	    128	  21494	   53f6	drivers/tty/serial/meson_uart.o
down to:
   15415	   4784	    128	  20327	   4f67	drivers/tty/serial/meson_uart.o

Reviewed-by: Neil Armstrong <narmstrong@baylibre.com>
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Link: https://lore.kernel.org/r/3f18638cb3cf08ed8817addca1402ed5e3bd3602.1661328361.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>