sh_eth: fix typo in RX descriptor bit name

The correct name of the RX descriptor 0 bit 30 is RDLE (receive descriptor
list end),  not  RDEL.

Signed-off-by: Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>
Signed-off-by: David S. Miller <davem@davemloft.net>