Find examples directory when invoked out of tree

Change-Id: I5d5a7024c5145b0acd5961f4b942bbff635e94cb
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/pimgen.py b/pimgen.py
index 1b10dd9..b511dd4 100755
--- a/pimgen.py
+++ b/pimgen.py
@@ -29,7 +29,7 @@
         default='generated.cpp', help='Output file name.')
     parser.add_argument(
         '-d', '--dir', dest='inputdir',
-        default='example',
+        default=os.path.join(script_dir, 'example'),
         help='Location of files to process.')
 
     args = parser.parse_args()