staging: vt6655: Convert macro vt6655_mac_word_reg_bits_off to function

Convert macro vt6655_mac_word_reg_bits_off to function.
checkpatch.pl does not accept multiline macros.

Signed-off-by: Philipp Hortmann <philipp.g.hortmann@gmail.com>
Link: https://lore.kernel.org/r/04fb37871c4d383c27287934a0dddb3aa7974b08.1657657918.git.philipp.g.hortmann@gmail.com


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