pinctrl: renesas: rzg2l: Fix locking in rzg2l_dt_subnode_to_map()

Commit d3aaa720 ("pinctrl: renesas: rzg2l: Add pin configuration
support for pinmux groups") introduced the possibility to parse pin
configuration for pinmux groups. It did that by calling
rzg2l_map_add_config() at the end of rzg2l_dt_subnode_to_map() and
jumping to the remove_group label in case rzg2l_map_add_config() failed.
But if that happens, the mutex will already be unlocked, thus this it will
lead to double mutex unlock operation. To fix this move the
rzg2l_map_add_config() call just after all the name argument is ready and
before the mutex is locked. There is no harm in doing this, as this only
parses the data from device tree that will be further processed by
pinctrl core code.

Fixes: d3aaa720

 ("pinctrl: renesas: rzg2l: Add pin configuration support for pinmux groups")
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/all/f8c3a3a0-7c48-4e40-8af0-ed4e9d9b049f@moroto.mountain
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://lore.kernel.org/r/20240115153453.99226-1-claudiu.beznea.uj@bp.renesas.com
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>