defconfig: hardcode toolchain

Change-Id: I96dab3f10acd4449775ea0e9c5befb1526d0b12c
fs/namespace: fix -Wmaybe-uninitialized error

Change-Id: I1a1a2ab7372011855cb27e3c5320b5325b9d57db
bluetooth: fix -Wsizeof-pointer-memaccess error

Change-Id: Iec0ed2d2309467032d3e4caffc4955f7fa34ed5d