staging: vt6655: Convert macro vt6655_mac_reg_bits_off to function

Convert macro vt6655_mac_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/422950c8e1349fba2f97b0b95ba13f361cde05d9.1657657918.git.philipp.g.hortmann@gmail.com


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