Floss: Don't crash when chipset is broken

There are a few known issues in some chipsets of ChromeOS which would
break some assertion in HAL randomly. This CL removes those assertion
for Floss and make btadapterd catch the raise.

Bug: 287570078
Bug: 227395826
Tag: #floss
Test: enable Floss and then run 'rmmod btusb'. make sure there is no
crash.
Test: run usbreset and verify btadapterd can be restarted and there is
no crash.
Test: mma -j32

Change-Id: I6de4187cab0994eca771bc6ad546b8373d546f97