net: hisilicon: hns: Replace mdelay() with msleep()

hns_ppe_common_init_hw() and hns_xgmac_init() are never
called in atomic context.
They call mdelay() to busily wait, which is not necessary.
mdelay() can be replaced with msleep().

This is found by a static analysis tool named DCNS written by myself.

Signed-off-by: Jia-Ju Bai <baijiaju1990@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>