drivers: base: Add generic cross-process locking API

Add a generic locking API for situations where multiple user-space
processes and/or kernel drivers need to cooordinate access to a
shared resource such as a graphics buffer.

Change-Id: Ic0dedbad74b970d7bd1a6624a845b5b1b9847443
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
diff --git a/include/linux/Kbuild b/include/linux/Kbuild
index 2252c8b..1a606b5 100644
--- a/include/linux/Kbuild
+++ b/include/linux/Kbuild
@@ -428,3 +428,4 @@
 header-y += tzcom.h
 header-y += qcedev.h
 header-y += idle_stats_device.h
+header-y += genlock.h