net: stmmac: Use bfsize1 in ndesc_init_rx_desc

gcc warn this:

drivers/net/ethernet/stmicro/stmmac/norm_desc.c: In function ndesc_init_rx_desc:
drivers/net/ethernet/stmicro/stmmac/norm_desc.c:138:6: warning: variable 'bfsize1' set but not used [-Wunused-but-set-variable]

Like enh_desc_init_rx_desc, we should use bfsize1
in ndesc_init_rx_desc to calculate 'p->des1'

Fixes: 583e6361 ("net: stmmac: use correct DMA buffer size in the RX descriptor")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Aaro Koskinen <aaro.koskinen@nokia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>