net: wangxun: clean up the code

Convert various mult-bit fields to be defined using GENMASK/FIELD_PREP.
Simplify the code with the ternary operator.

Signed-off-by: Mengyuan Lou <mengyuanlou@net-swift.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Link: https://lore.kernel.org/r/20230116103839.84087-1-mengyuanlou@net-swift.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>