staging: vt6655: Convert macro vt6655_mac_read_ether_addr to function

Convert macro vt6655_mac_read_ether_addr to static function.
checkpatch.pl does not accept multiline macros.

Signed-off-by: Philipp Hortmann <philipp.g.hortmann@gmail.com>
Link: https://lore.kernel.org/r/2e2524187d9d3a6140fe4a5a35926db14dddfe98.1656835310.git.philipp.g.hortmann@gmail.com


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