staging: vt6655: Change camel case variables to snake case

Change camel case to snake case and remove the unneeded "by" prefix.
Issue found by checkpatch.

Signed-off-by: Mingzai Sun <szp2017@gmail.com>
Link: https://lore.kernel.org/r/20230812151710.462685-1-szp2017@gmail.com


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