Now that the FULL_OPTIMIZATION for gtk+ has been enabled in the core
tune-atom.inc, it is no longer necessary to do so for every atom based
bsp.

Signed-off-by: Darren Hart <dvhart@linux.intel.com>
CC: Tom Zanussi <tom.zanussi@intel.com>
CC: Ke Yu <ke.yu@intel.com>
CC: Richard Purdie <richard.purdie@intel.com>