dt-bindings: fpga: update link for Altera's and AMD partial recon

The link is giving the 404 error, so use the correct link for the
documents

Signed-off-by: Dinh Nguyen <[e-mail]>
Acked-by: Krzysztof Kozlowski <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Reviewed-by: Xu Yilun <[e-mail]>
Signed-off-by: Xu Yilun <[e-mail]>

Documentation/devicetree/bindings/fpga/fpga-region.yaml

···
   FPGA Bridges that exist on the FPGA fabric prior to the partial reconfiguration.
 
   --
-  [1] www.altera.com/content/dam/altera-www/global/en_US/pdfs/literature/ug/ug_partrecon.pdf
+  [1] https://www.intel.com/programmable/technical-pdfs/683404.pdf
   [2] tspace.library.utoronto.ca/bitstream/1807/67932/1/Byma_Stuart_A_201411_MAS_thesis.pdf
-  [3] https://www.xilinx.com/support/documentation/sw_manuals/xilinx14_1/ug702.pdf
+  [3] https://docs.amd.com/v/u/en-US/ug702
 
 properties:
   $nodename: