Add mISDN driver

mISDN is a new modular ISDN driver, in the long term it should replace
the old I4L driver architecture for passiv ISDN cards.

Signed-off-by: Karsten Keil <kkeil@suse.de>
diff --git a/Documentation/isdn/README.mISDN b/Documentation/isdn/README.mISDN
new file mode 100644
index 0000000..cd8bf92
--- /dev/null
+++ b/Documentation/isdn/README.mISDN
@@ -0,0 +1,6 @@
+mISDN is a new modular ISDN driver, in the long term it should replace
+the old I4L driver architecture for passiv ISDN cards.
+It was designed to allow a broad range of applications and interfaces
+but only have the basic function in kernel, the interface to the user
+space is based on sockets with a own address family AF_ISDN.
+