clk: renesas: cpg-mssr: Fix 'soc' node handling in cpg_mssr_reserved_init()

clk: renesas: cpg-mssr: Fix 'soc' node handling in cpg_mssr_reserved_init()

A device_node reference obtained via of_find_node_by_path() requires
explicit calls to of_node_put() after it is no longer required to avoid
leaking the resource.

Instead of adding the missing calls to of_node_put() in all execution
paths, use the cleanup attribute for 'soc' by means of the __free()
macro, which automatically calls of_node_put() when the variable goes
out of scope.

Fixes: 6aa175476490 ("clk: renesas: cpg-mssr: Ignore all clocks assigned to non-Linux system")
Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/20241031-clk-renesas-cpg-mssr-cleanup-v2-1-0010936d1154@gmail.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>