ATM: Delete no use FILL_RX_POOLS_IN_BH marco

The macro FILL_RX_POOLS_IN_BH is never been used, in order to avoid
the compiler reports error because of the usage of function INIT_WORK,
we just delete the marco.

Cc: Chas Williams <chas@cmf.nrl.navy.mil>
Cc: linux-atm-general@lists.sourceforge.net
Signed-off-by: Wang Shaoyan <wangshaoyan.pt@taobao.com>
Signed-off-by: David S. Miller <davem@davemloft.net>