leds: max5970: Make use of dev_err_probe()

Simplify the error handling in probe function by switching from
dev_err() to dev_err_probe().

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20231214184050.1272848-4-andriy.shevchenko@linux.intel.com
Signed-off-by: Lee Jones <lee@kernel.org>