tools: moveconfig: add Xtensa GCC prefix to CROSS_COMPILE list

This is needed to move CONFIG options for the recently-added
xtfpga_defconfig.

The tarball of the pre-built toolchain can be downloaded from:
https://www.kernel.org/pub/tools/crosstool/files/bin/x86_64/4.9.0/

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
1 file changed