EDAC/synopsys: Add a SPDX identifier

Replace the copyright boilerplate with a SPDX identifier.

  [ bp: Rewrite commit message. ]

Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220428044051.2842687-1-shubhrajyoti.datta@xilinx.com