staging: vt6655: Rename function MACbIsRegBitsOff

staging: vt6655: Rename function MACbIsRegBitsOff

Remove declaration of MACbIsRegBitsOff as it is not needed. Rename
function MACbIsRegBitsOff to vt6655_mac_is_reg_bits_off, rename
byRegOfs to reg_offset and byTestBits to mask to avoid CamelCase which
is not accepted by checkpatch.pl. Made function static to keep namespace
clean.

Signed-off-by: Philipp Hortmann <philipp.g.hortmann@gmail.com>
Link: https://lore.kernel.org/r/79530d864d4e39e29b899b80f2e2ecf0566366dc.1661666677.git.philipp.g.hortmann@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>