pwm: adp5585: Set OSC_EN bit to 1 when PWM state is enabled

It turns out that OSC_EN bit in GERNERAL_CFG register has to be set to 1
when PWM state is enabled, otherwise PWM signal won't be generated.

Fixes: e9b503879fd2 ("pwm: adp5585: Add Analog Devices ADP5585 support")
Signed-off-by: Liu Ying <[e-mail]>
Reviewed-by: Laurent Pinchart <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Uwe Kleine-König <[e-mail]>

drivers/pwm/pwm-adp5585.c

···
 	if (ret)
 		return ret;
 
+	ret = regmap_set_bits(regmap, ADP5585_GENERAL_CFG, ADP5585_OSC_EN);
+	if (ret)
+		return ret;
+
 	return regmap_set_bits(regmap, ADP5585_PWM_CFG, ADP5585_PWM_EN);
 }