BLE: Do not rewrite devtype in BTM_ReadDevInfo()

During a classic pairing process, receiving new inq results may turn
devtype info LE and stop the followiing SDP process. Also, it's
relatively impossible to change device type.

Bug: 263544601
Test: atest BluetoothInstrumentationTests
Change-Id: I9a2ca1210114b60d1f26bf61939a93f6f28f1e16