staging: vt6656: Use BIT() macro in vnt_mac_reg_bits_* functions

The last parameter in the functions vnt_mac_reg_bits_on and
vnt_mac_reg_bits_off defines the bits to set or unset. So, it's more
clear to use the BIT() macro instead of an hexadecimal value.

Signed-off-by: Oscar Carter <oscar.carter@gmx.com>
Link: https://lore.kernel.org/r/20200320181326.12156-1-oscar.carter@gmx.com


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