net: wireless: bcm4329: Remove unused presto directory.

Change-Id: Iddc3e7999434668a8b9cbc537e0e0de205ee2277
Kernel script: Change Toolchain to "arm-eabi-4.7".

This is the default toolchain that is used in cm-11.0.

Change-Id: Iaf85df39f08b5e5d1d98fda00e16c724b0e23d21