Fix mismatched signatures for the wide interface

Lists are passed by-reference from python code, and so should be
&CSlice<_> not CSlice<_>.

src/runtime/src/kernel/dma.rs

@@ -116,7 +116,7 @@ pub extern "C" fn dma_record_output(target: i32, word: i32) {
     }
 }
 
-pub extern "C" fn dma_record_output_wide(target: i32, words: CSlice<i32>) {
+pub extern "C" fn dma_record_output_wide(target: i32, words: &CSlice<i32>) {
     assert!(words.len() <= 16); // enforce the hardware limit
 
     unsafe {

src/runtime/src/rtio_csr.rs

@@ -107,7 +107,7 @@ pub extern "C" fn output(target: i32, data: i32) {
     }
 }
 
-pub extern "C" fn output_wide(target: i32, data: CSlice<i32>) {
+pub extern "C" fn output_wide(target: i32, data: &CSlice<i32>) {
     unsafe {
         csr::rtio::target_write(target as u32);
         // writing target clears o_data