net/mlx5: DR, use non preemptible call to get the current cpu number

Use raw_smp_processor_id instead of smp_processor_id() otherwise we will
get the following trace in debug-kernel:
	BUG: using smp_processor_id() in preemptible [00000000] code: devlink
	caller is dr_create_cq.constprop.2+0x31d/0x970 [mlx5_core]
	Call Trace:
	dump_stack+0x9a/0xf0
	debug_smp_processor_id+0x1f3/0x200
	dr_create_cq.constprop.2+0x31d/0x970
	genl_family_rcv_msg+0x5fd/0x1170
	genl_rcv_msg+0xb8/0x160
	netlink_rcv_skb+0x11e/0x340

Fixes: 297ccceb

 ("net/mlx5: DR, Expose an internal API to issue RDMA operations")
Signed-off-by: Erez Shitrit <erezsh@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>