Don't panic if kernel file name is shorter than 11 chars

Author: phil-opp

src/fat.rs

@@ -36,7 +36,7 @@ pub fn create_fat_filesystem(
             let converted = name.to_string_lossy();
             let name = converted.as_bytes();
             let mut new_label = [0u8; 11];
-            let name = &name[..new_label.len()];
+            let name = &name[..usize::min(new_label.len(), name.len())];
             let slice = &mut new_label[..name.len()];
             slice.copy_from_slice(name);
             label = new_label;