net: mscc: ocelot: remove unused variable 'vcap_data_t'

Fix sparse warning:

drivers/net/ethernet/mscc/ocelot_ace.c:96:3:
 warning: symbol 'vcap_data_t' was not declared. Should it be static?

'vcap_data_t' never used so can be removed

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>