* CONFIG_SOC is now properly set and we do not need a separate
XTENSA_CORE build variable
* Some unnecessary macro -D CFLAGS in the Xtensa Makefile removed
* There is no default SOC selection, it is now done explicitly in
the board's defconfig
* CONFIG_<board name> now renamed to CONFIG_SOC_<board name in
uppercase> to conform to established style.
Issue: ZEP-1711
Change-Id: I88997530db09970b7fdd1c3e3d355bfca9d0be1a
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>