powerpc: dts: p2020: Add fsl/p2020si-pre.dtsi and fsl/p2020si-post.dtsi symlinks

P2020 DTS files in upstream Linux kernel use fsl/p2020si-pre.dtsi and
fsl/p2020si-post.dtsi include device tree files.

Add symlinks for these include device tree files into U-Boot powerpc
directory and points them to U-Boot inline device tree files p2020.dtsi and
p2020-post.dtsi.

This allows to use P2020 DTS files from upstream Linux kernel in U-Boot.

Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Priyanka Jain <priyanka.jain@nxp.com>

diff --git a/arch/powerpc/dts/fsl/p2020si-post.dtsi b/arch/powerpc/dts/fsl/p2020si-post.dtsi
new file mode 120000 (symlink)
index 0000000..b51ebf5
--- /dev/null
+++ b/arch/powerpc/dts/fsl/p2020si-post.dtsi
@@ -0,0 +1 @@
+../p2020-post.dtsi
\ No newline at end of file

diff --git a/arch/powerpc/dts/fsl/p2020si-pre.dtsi b/arch/powerpc/dts/fsl/p2020si-pre.dtsi
new file mode 120000 (symlink)
index 0000000..1e4b16f
--- /dev/null
+++ b/arch/powerpc/dts/fsl/p2020si-pre.dtsi
@@ -0,0 +1 @@
+../p2020.dtsi
\ No newline at end of file