pinctrl: intel: Import PWM_LPSS namespace for devm_pwm_lpss_probe()

The Intel pinctrl driver can provide a PWM device and for that needs to
call the function devm_pwm_lpss_probe(). That function is provided by
the pwm-lpss driver which intends to export it in the "PWM_LPSS"
namespace. To prepare fixing the pwm-lpss driver to indeed use the
"PWM_LPSS" namespace, import that namespace when used.

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