target: Put TCMU under a new config option

Conceptually version 2 should be viewed as an entirely new, incompatible
version of TCMU, so emphasize this by changing the config option and
Kconfig text.

Signed-off-by: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
diff --git a/drivers/target/Kconfig b/drivers/target/Kconfig
index 81d44c4..2573612 100644
--- a/drivers/target/Kconfig
+++ b/drivers/target/Kconfig
@@ -31,12 +31,13 @@
 	Say Y here to enable the TCM/pSCSI subsystem plugin for non-buffered
 	passthrough access to Linux/SCSI device
 
-config TCM_USER
+config TCM_USER2
 	tristate "TCM/USER Subsystem Plugin for Linux"
 	depends on UIO && NET
 	help
 	Say Y here to enable the TCM/USER subsystem plugin for a userspace
-	process to handle requests
+	process to handle requests. This is version 2 of the ABI; version 1
+	is obsolete.
 
 source "drivers/target/loopback/Kconfig"
 source "drivers/target/tcm_fc/Kconfig"