net-caif: add CAIF Kconfig and Makefiles

Kconfig and Makefiles with options for:
CAIF:        Including caif
CAIF_DEBUG:  CAIF Debug
CAIF_NETDEV: CAIF Network Device for GPRS Contexts

Signed-off-by: Sjur Braendeland <sjur.brandeland@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/Kconfig b/net/Kconfig
index 6851464..e10d55c 100644
--- a/net/Kconfig
+++ b/net/Kconfig
@@ -280,5 +280,7 @@
 
 source "net/rfkill/Kconfig"
 source "net/9p/Kconfig"
+source "net/caif/Kconfig"
+
 
 endif   # if NET