With CONFIG_DEBUG_PREEMPT enabled, a warning was seen on device
creation. This occurs due to the incorrect cpu API usage in
ndo_get_stats64 handler.

BUG: using smp_processor_id() in preemptible [00000000] code: rmnetcli/5743
caller is debug_smp_processor_id+0x1c/0x24
Call trace:
[<ffffff9d48c8967c>] dump_backtrace+0x0/0x2a8
[<ffffff9d48c89bbc>] show_stack+0x20/0x28
[<ffffff9d4901fff8>] dump_stack+0xa8/0xe0
[<ffffff9d490421e0>] check_preemption_disabled+0x104/0x108
[<ffffff9d49042200>] debug_smp_processor_id+0x1c/0x24
[<ffffff9d494a36b0>] rmnet_get_stats64+0x64/0x13c
[<ffffff9d49b014e0>] dev_get_stats+0x68/0xd8
[<ffffff9d49d58df8>] rtnl_fill_stats+0x54/0x140
[<ffffff9d49b1f0b8>] rtnl_fill_ifinfo+0x428/0x9cc
[<ffffff9d49b23834>] rtmsg_ifinfo_build_skb+0x80/0xf4
[<ffffff9d49b23930>] rtnetlink_event+0x88/0xb4
[<ffffff9d48cd21b4>] raw_notifier_call_chain+0x58/0x78
[<ffffff9d49b028a4>] call_netdevice_notifiers_info+0x48/0x78
[<ffffff9d49b08bf8>] __netdev_upper_dev_link+0x290/0x5e8
[<ffffff9d49b08fcc>] netdev_master_upper_dev_link+0x3c/0x48
[<ffffff9d494a2e74>] rmnet_newlink+0xf0/0x1c8
[<ffffff9d49b23360>] rtnl_newlink+0x57c/0x6c8
[<ffffff9d49b2355c>] rtnetlink_rcv_msg+0xb0/0x244
[<ffffff9d49b5230c>] netlink_rcv_skb+0xb4/0xdc
[<ffffff9d49b204f4>] rtnetlink_rcv+0x34/0x44
[<ffffff9d49b51af0>] netlink_unicast+0x1ec/0x294
[<ffffff9d49b51fdc>] netlink_sendmsg+0x320/0x390
[<ffffff9d49ae6858>] sock_sendmsg+0x54/0x60
[<ffffff9d49ae91bc>] SyS_sendto+0x1a0/0x1e4
[<ffffff9d48c83770>] el0_svc_naked+0x24/0x28

Fixes: 192c4b5d ("net: qualcomm: rmnet: Add support for 64 bit stats")
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Signed-off-by: David S. Miller <davem@davemloft.net>