flo: Disable diag device in normal mode.

Remove the diag device when the device is in normal mode.

Bug: 18203257
Change-Id: I878ac648c49ef0940d55d5b6695bac24742847c8
merge in lmp-release history after reset to lmp-dev
merge in lmp-release history after reset to lmp-dev
Merge remote-tracking branch 'upstream/lollipop-release' into aosp-lolli