ipg.c: remove id [SUNDANCE, 0x1021]

ipg.c:
  The id [SUNDANCE, 0x1021] (=[0x13f0, 0x1021]) is defined
  at dl2k.h and ipg.c.
  But this device works better with dl2k driver.

  This problem is similar with the commit
  [25cca535
  ipg: Remove device claimed by dl2k from pci id table]
  at 11 Feb 2010.

Signed-off-by: Ken Kawasaki <ken_kawasaki@spring.nifty.jp>
Signed-off-by: David S. Miller <davem@davemloft.net>