client: Fix beta clippy issue (unnecessary_cast)

warning: casting raw pointers to the same type and constness is unnecessary (`*const u8` -> `*const u8`)
   --> src/lib.rs:603:28
    |
603 |         let cap_data_ptr = cap_data.as_ptr() as *const u8;
    |                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ help: try: `cap_data.as_ptr()`
    |
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#unnecessary_cast
    = note: `#[warn(clippy::unnecessary_cast)]` on by default

Signed-off-by: Rob Bradford <[email protected]>

src/lib.rs

@@ -600,7 +600,7 @@ impl Client {
         let mmap_cap_size = size_of::<vfio_region_info_cap_sparse_mmap>() as u32;
         let mmap_area_size = size_of::<vfio_region_sparse_mmap_area>() as u32;
 
-        let cap_data_ptr = cap_data.as_ptr() as *const u8;
+        let cap_data_ptr = cap_data.as_ptr();
         let mut region_info_offset = region_info.cap_offset;
         while region_info_offset != 0 {
             // calculate the offset from the begining of the cap_data based on the offset