devtool/standard.py: Update devtool modify to copy source from work-shared if its already downloaded
In the regular devtool modify flow, the kernel source is fetched by
running do_fetch task. This is an overhead in time and space.
This patch updates modify command to check if the kernel source is
already downloaded. If so, then instead of calling do_fetch, copy the
source from work-shared to devtool workspace by creating hard links
else run the usual devtool modify flow and call do_fetch task.
[YOCTO #10416]
Signed-off-by: Sai Hari Chandana Kalluri <chandana.kalluri@xilinx.com> Signed-off-by: Alejandro Enedino Hernandez Samaniego <alejandr@xilinx.com> Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
