tcmode-external-xilinx.inc: Remove stale include
tcmode-external-xilinx.inc: Remove stale include

Remove tcmode external xilinx which was used for MB toolchain binaries.
This is no longer needed due to removal of binary toolchain recipes in
commit 21541f65bb7e4c8837105bcd8fce153227afb554

Signed-off-by: Manjukumar Matha <4c64a17569570cb9f1048973bce031c402b55312@xilinx.com>

Xilinx/meta-petalinux,Xilinx/meta-petalinux,Xilinx/meta-petalinux,Xilinx/meta-petalinux,Xilinx/meta-petalinux,Xilinx/meta-petalinux