ethtool: move to its own directory

The ethtool netlink interface is going to be split into multiple files so
that it will be more convenient to put all of them in a separate directory
net/ethtool. Start by moving current ethtool.c with ioctl interface into
this directory and renaming it to ioctl.c.

Signed-off-by: Michal Kubecek <[e-mail]>
Acked-by: Jiri Pirko <[e-mail]>
Reviewed-by: Florian Fainelli <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/Makefile

···
 
 # LLC has to be linked before the files in net/802/
 obj-$(CONFIG_LLC)		+= llc/
-obj-$(CONFIG_NET)		+= ethernet/ 802/ sched/ netlink/ bpf/
+obj-$(CONFIG_NET)		+= ethernet/ 802/ sched/ netlink/ bpf/ ethtool/
 obj-$(CONFIG_NETFILTER)		+= netfilter/
 obj-$(CONFIG_INET)		+= ipv4/
 obj-$(CONFIG_TLS)		+= tls/

net/core/Makefile

···
 
 obj-$(CONFIG_SYSCTL) += sysctl_net_core.o
 
-obj-y		     += dev.o ethtool.o dev_addr_lists.o dst.o netevent.o \
+obj-y		     += dev.o dev_addr_lists.o dst.o netevent.o \
 			neighbour.o rtnetlink.o utils.o link_watch.o filter.o \
 			sock_diag.o dev_ioctl.o tso.o sock_reuseport.o \
 			fib_notifier.o xdp.o flow_offload.o

net/ethtool/Makefile

···
+# SPDX-License-Identifier: GPL-2.0-only
+
+obj-y		+= ioctl.o