gitattributes: handle patches as binaries

Avoid line ending conversions.

.gitattributes

@@ -2,11 +2,11 @@
 *           text eol=lf
 
 # Patches.
-*.diff      text=auto
-*.patch     text=auto
-*.patch32   text=auto
-*.patch64   text=auto
-*.patch.*   text=auto
+*.diff      text=binary
+*.patch     text=binary
+*.patch32   text=binary
+*.patch64   text=binary
+*.patch.*   text=binary
 
 # Powershell scripts.
 *.ps1       text eol=crlf