Staging: add cowloop to the build

Now that the code can build, let's add it to the build system.

Cc: "H.J. Thomassen" <hjt@ATComputing.nl>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/staging/Kconfig b/drivers/staging/Kconfig
index 2b3c0c4..ee073ce 100644
--- a/drivers/staging/Kconfig
+++ b/drivers/staging/Kconfig
@@ -141,5 +141,7 @@
 
 source "drivers/staging/iio/Kconfig"
 
+source "drivers/staging/cowloop/Kconfig"
+
 endif # !STAGING_EXCLUDE_BUILD
 endif # STAGING