ACL: No need to clear these flags

It's done in btm_sec.cc btm_sec_disconnected:

p_dev_rec->sec_flags &=
        ~(BTM_SEC_AUTHENTICATED | BTM_SEC_ENCRYPTED | BTM_SEC_ROLE_SWITCHED |
          BTM_SEC_16_DIGIT_PIN_AUTHED);

Bug: 159815595
Tag: #refactor
Test: compile & verify basic functions working
Change-Id: Iea4cac99b6691b0cfe765ee5eb109f25339ebd5a