pwm: lpss: Rename pwm_lpss_probe() --> devm_pwm_lpss_probe()

The pwm_lpss_probe() uses managed resources. Show this to
the users explicitly by adding devm prefix to its name.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>