samples: move auxdisplay example code from Documentation

Move auxdisplay examples to samples and remove it from Documentation
Makefile. Create a new Makefile to build auxdisplay. It can be built
from top level directory or from auxdisplay directory:

Run make -C samples/auxdisplay or cd samples/auxdisplay; make

Acked-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
diff --git a/Documentation/auxdisplay/cfag12864b b/Documentation/auxdisplay/cfag12864b
index eb7be39..12fd51b 100644
--- a/Documentation/auxdisplay/cfag12864b
+++ b/Documentation/auxdisplay/cfag12864b
@@ -101,5 +101,5 @@
 Also, you can mmap the framebuffer: open & mmap, munmap & close...
 which is the best option for most uses.
 
-Check Documentation/auxdisplay/cfag12864b-example.c
+Check samples/auxdisplay/cfag12864b-example.c
 for a real working userspace complete program with usage examples.