fix(scheme/itimer): wrong chunk size

Chunk size of the scheme (`size_of::<ITimerScheme>() == 0`) was being
provided instead of `size_of::<ITimerSpec>()`. This resulted in a kernel
panic (division by zero) when kread was called for this scheme.

Signed-off-by: Anhad Singh <andypython@protonmail.com>

src/scheme/itimer.rs

@@ -69,7 +69,7 @@ impl KernelScheme for ITimerScheme {
 
         let mut specs_read = 0;
 
-        for current_chunk in buf.in_exact_chunks(mem::size_of::<ITimerScheme>()) {
+        for current_chunk in buf.in_exact_chunks(mem::size_of::<ITimerSpec>()) {
             current_chunk.copy_exactly(&ITimerSpec::default())?;
 
             specs_read += 1;