net: wangxun: cleanup the code in wx_set_coalesce()

Cleanup the code for the next patch to add adaptive RX coalesce.

Signed-off-by: Jiawen Wu <jiawenwu@trustnetic.com>
Reviewed-by: Michal Swiatkowski <michal.swiatkowski@linux.intel.com>
Link: https://patch.msgid.link/20250821023408.53472-4-jiawenwu@trustnetic.com


Signed-off-by: Jakub Kicinski <kuba@kernel.org>