staging: vboxvideo: Rename uint32_t type to u32

Issue found by checkpatch.

CHECK: Prefer kernel type 'u32' over 'uint32_t'
+static const uint32_t vbox_cursor_plane_formats[] = {

CHECK: Prefer kernel type 'u32' over 'uint32_t'
+static const uint32_t vbox_primary_plane_formats[] = {

CHECK: Prefer kernel type 'u32' over 'uint32_t'
+       const uint32_t *formats;

Signed-off-by: Ricardo Reis Marques Silva <ricardormsilva93@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>