Kernel: Don't crash on writes to ProcFS

Author: https://github.com/BenWiederhake
Commit: e3b7c305bc
Pull-request: https://github.com/SerenityOS/serenity/pull/10661
Reviewed-by: https://github.com/ADKaster
Reviewed-by: https://github.com/IdanHo
Reviewed-by: https://github.com/awesomekling
Reviewed-by: https://github.com/bcoles

Kernel/FileSystem/ProcFS.cpp

@@ -244,7 +244,7 @@ ProcFSProcessAssociatedInode::ProcFSProcessAssociatedInode(const ProcFS& fs, Pro
 
 KResultOr<size_t> ProcFSProcessAssociatedInode::write_bytes(off_t, size_t, const UserOrKernelBuffer&, OpenFileDescription*)
 {
-    VERIFY_NOT_REACHED();
+    return ENOTSUP;
 }
 
 KResultOr<NonnullRefPtr<ProcFSProcessDirectoryInode>> ProcFSProcessDirectoryInode::try_create(const ProcFS& procfs, ProcessID pid)