EDAC: Fix wrong executable file modes for C source files

Three EDAC source files were mistakenly marked as executable when adding the
EDAC scrub controls.

These are plain C source files and should not carry the executable bit.
Correcting their modes follows the principle of least privilege and avoids
unnecessary execute permissions in the repository.

  [ bp: Massage commit message. ]

Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/20250828191954.903125-1-visitorckw@gmail.com

Author: visitorckw