net: wangxun: Fix vector length of interrupt cause

There is 64-bit interrupt cause register for txgbe. Fix to clear upper
32 bits.

Fixes: 3f703186

 ("net: libwx: Add irq flow functions")
Signed-off-by: Jiawen Wu <jiawenwu@trustnetic.com>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Link: https://lore.kernel.org/r/20230322103632.132011-1-jiawenwu@trustnetic.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>