ACPI: battery: Check for error code from devm_mutex_init() call

Even if it's not critical, the avoidance of checking the error code
from devm_mutex_init() call today diminishes the point of using devm
variant of it. Tomorrow it may even leak something. Add the missed
check.

Fixes: 0710c1ce ("ACPI: battery: initialize mutexes through devm_ APIs")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://patch.msgid.link/20241030162754.2110946-1-andriy.shevchenko@linux.intel.com


[ rjw: Added 2 empty code lines ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>