net: ceph: Fix a typo in osdmap.c

Modify "inital" to "initial" in net/ceph/osdmap.c.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Lu Wei <luwei32@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>