nvme: move sysfs code to a dedicated sysfs.c file

The core.c file became long and hard to maintain. Create a dedicated
file to centralize the sysfs functionality. This is a common practice to
separate sysfs/configfs related logic from the main driver logic .c file.
For example, in the nvmet module the configfs interface has its own
dedicated file.

This patch does not include any functional changes.
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Max Gurtovoy <mgurtovoy@nvidia.com>
[merged dhchap memleak fixes, include nvme-auth.h]
Signed-off-by: Keith Busch <kbusch@kernel.org>

drivers/nvme/host/Makefile

@@ -10,7 +10,7 @@ obj-$(CONFIG_NVME_FC)			+= nvme-fc.o
 obj-$(CONFIG_NVME_TCP)			+= nvme-tcp.o
 obj-$(CONFIG_NVME_APPLE)		+= nvme-apple.o
 
-nvme-core-y				+= core.o ioctl.o
+nvme-core-y				+= core.o ioctl.o sysfs.o
 nvme-core-$(CONFIG_NVME_VERBOSE_ERRORS)	+= constants.o
 nvme-core-$(CONFIG_TRACING)		+= trace.o
 nvme-core-$(CONFIG_NVME_MULTIPATH)	+= multipath.o

drivers/nvme/host/nvme.h

@@ -860,7 +860,11 @@ extern const struct attribute_group *nvme_ns_id_attr_groups[];
 extern const struct pr_ops nvme_pr_ops;
 extern const struct block_device_operations nvme_ns_head_ops;
 extern const struct attribute_group nvme_dev_attrs_group;
+extern const struct attribute_group *nvme_subsys_attrs_groups[];
+extern const struct attribute_group *nvme_dev_attr_groups[];
+extern const struct block_device_operations nvme_bdev_ops;
 
+void nvme_delete_ctrl_sync(struct nvme_ctrl *ctrl);
 struct nvme_ns *nvme_find_path(struct nvme_ns_head *head);
 #ifdef CONFIG_NVME_MULTIPATH
 static inline bool nvme_ctrl_use_ana(struct nvme_ctrl *ctrl)