staging: vt6656: Change macro to function and moved to better file

This patch fixes the checkpatch.pl warning like:
- CHECK: Macro argument reuse 'uVar' - possible side-effects?
Moved the only twice used function to the file where it is used.

Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Philipp Hortmann <philipp.g.hortmann@gmail.com>
Link: https://lore.kernel.org/r/fa37dde640cfe5093ff23ca0881aba4673751a49.1645477326.git.philipp.g.hortmann@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>