CAPI: Remove experimental tag from middleware feature

Despite all its bugs, the middleware support of our CAPI stack was
already in use for many, many moons. And after going through its code,
fixing all issues I found, I feel it deserves to officially become a
non-experimental feature.
Signed-off-by: NJan Kiszka <jan.kiszka@web.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/isdn/capi/Kconfig

@@ -17,8 +17,7 @@ config CAPI_TRACE
 	  If unsure, say Y.
 
 config ISDN_CAPI_MIDDLEWARE
-	bool "CAPI2.0 Middleware support (EXPERIMENTAL)"
-	depends on EXPERIMENTAL
+	bool "CAPI2.0 Middleware support"
 	help
 	  This option will enhance the capabilities of the /dev/capi20
 	  interface.  It will provide a means of moving a data connection,