SOF GCC v13

Support for SOF GCC13 targets.

SOF GCC11 Compilers (alpha)

GCC11 C and C++ compilers with GDB11 for SOF xtensa targets.

SOF GCC10.x compilers

Xtensa GCC 10.x, GDB 9.x compiler binaries and newlib for DSPs used by SOF.

UPDATE 5th August 2021
Add toolchain for imx8ulp.

UPDATE 26th March 2021
Bug fixed in xtensa-overlay for hsw and cnl targets. No ct-NG changes. New binaries for xtensa-hsw-elf and xtensa-cnl-elf attached.