usb-c: clear cache cc_voltage variable.

when not clearing cc_voltage the type-c current limit
will only be reported on the first plug in.

Signed-off-by: Johan Carlsson <johan.carlsson@teenage.engineering>

subsys/usb/usb_c/usbc_tc_snk_states.c

@@ -205,6 +205,9 @@ void tc_attached_snk_entry(void *obj)
 
 	LOG_INF("Attached.SNK");
 
+	/* Clear cached CC voltage */
+	tc->cc_voltage = TC_CC_VOLT_OPEN;
+
 	/* Set CC polarity */
 	ret = tcpc_set_cc_polarity(tcpc, tc->cc_polarity);
 	if (ret != 0) {