net: fec_ptp: add clock rate zero check

stable inclusion
from stable-5.10.46
commit 4f6e7098f19b8554470f6ad28030d1550c0bd983
bugzilla: 168323
CVE: NA

--------------------------------

commit cb3cefe3 upstream.

Add clock rate zero check to fix coverity issue of "divide by 0".

Fixes: commit 85bd1798 ("net: fec: fix spin_lock dead lock")
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Chen Jun <chenjun102@huawei.com>
Acked-by: Weilong Chen <chenweilong@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>