be2net: remove superfluous externs

This fixes some sparse warnings:
drivers/net/benet/be_cmds.c:1503:12: warning: function
	'be_cmd_enable_magic_wol' with external linkage has definition
drivers/net/benet/be_cmds.c:1668:12: warning: function
	'be_cmd_get_seeprom_data' with external linkage has definition

Signed-off-by: Dan Carpenter <error27@gmail.com>
Acked-by: Sarveshwar Bandi <sarveshwarb@serverengines.com>
Signed-off-by: David S. Miller <davem@davemloft.net>