xrt_git.bb: Fix xrt recipe for externalsrc
xrt_git.bb: Fix xrt recipe for externalsrc

Having WORKDIR in LIC_FILES_CHKSUM will cause externalsrc to break.
Change the LIC_FILES_CHKSUM to exclude the ${WORKDIR}

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

Xilinx/meta-xilinx,Xilinx/meta-xilinx,Xilinx/meta-xilinx,Xilinx/meta-xilinx,Xilinx/meta-xilinx,Xilinx/meta-xilinx