mfd: fusb302: fix dp detection error when increasing i2c frequency

If the timer_mux is started again after the N_DEBOUNCE_CNT+1 detection is completed,
the PD detection process may be mistakenly closed in the fusb_state_src_send_caps(),
resulting in failure to detect dp.

  step1:
         when fusb_state_attach_wait_source set conn_state to "attached_source", it will restart timer_mux_machine (1) with 2ms.
         Many i2c communications go on. conn_state == policy_src_send_caps
  step2:
         policy_src_send_caps would wait timer_mux_machine (T_NO_RESPONSE) to disabled PD detection
         until policy_send_data run succeed to close timer_mux_machine.
         state_machine_typec()

         static void fusb_state_src_send_caps(struct fusb30x_chip *chip, u32 evt)
         switch (chip->sub_state) {
         case 1:
           tmp = policy_send_data(chip);
           if (tmp == tx_success) {
              ....
              chip->timer_mux = T_DISABLED; /* (2) close timer_mux */
           }
           ....
         default:
           if (evt & EVENT_TIMER_MUX) {
              ....
              set_state(chip, disabled); /* (3) just designed for T_NO_RESPONSE */
           }

  When (1) timerout event triggered before (2), it would mistakenly into (3).

solution:
    The N_DEBOUNCE_CNT+1 test is complete, do not start the timer_mux again.

Signed-off-by: Wang Jie <dave.wang@rock-chips.com>
Change-Id: I401ca594c875e8e5342b0e2cdfb602500c980a91

Author: Wang Jie

drivers/mfd/fusb302.c

@@ -1692,8 +1692,8 @@ static void fusb_state_attach_wait_source(struct fusb30x_chip *chip, u32 evt)
 					set_state(chip, attached_source);
 			} else {
 				set_state_unattached(chip);
-				return;
 			}
+			return;
 		}
 
 		chip->timer_mux = 2;