nvme: add the "debug" host driver

This patch adds a new driver "nvme-debug". It uses memory as a backing
store and it is used to test the copy offload functionality.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

drivers/nvme/host/Kconfig

@@ -83,3 +83,16 @@ config NVME_TCP
 	  from https://github.com/linux-nvme/nvme-cli.
 
 	  If unsure, say N.
+
+config NVME_DEBUG
+	tristate "NVM Express debug"
+	depends on INET
+	depends on BLOCK
+	select NVME_CORE
+	select NVME_FABRICS
+	select CRYPTO
+	select CRYPTO_CRC32C
+	help
+	  This pseudo driver simulates a NVMe adapter.
+
+	  If unsure, say N.

drivers/nvme/host/Makefile

@@ -8,6 +8,7 @@ obj-$(CONFIG_NVME_FABRICS)		+= nvme-fabrics.o
 obj-$(CONFIG_NVME_RDMA)			+= nvme-rdma.o
 obj-$(CONFIG_NVME_FC)			+= nvme-fc.o
 obj-$(CONFIG_NVME_TCP)			+= nvme-tcp.o
+obj-$(CONFIG_NVME_DEBUG)		+= nvme-debug.o
 
 nvme-core-y				:= core.o ioctl.o
 nvme-core-$(CONFIG_TRACING)		+= trace.o