net: stmmac: increase the timeout for dma reset

Current timeout value is not enough for gmac5 dma reset
on imx8mp platform, increase the timeout range.

Signed-off-by: Fugang Duan <fugang.duan@nxp.com>
Signed-off-by: Joakim Zhang <qiangqing.zhang@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>