Adjust util_is_printable_string() comment and fix test

This commit which changed the behaviour of this function broke one
of the tests. Also the comment should be updated to reflect its new
behaviour.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: David Gibson <david@gibson.dropbear.id.au>

tests/run_tests.sh

@@ -498,9 +498,10 @@ fdtget_tests () {
 
     # run_fdtget_test <expected-result> [<flags>] <file> <node> <property>
     run_fdtget_test "MyBoardName" $dtb / model
+    run_fdtget_test "MyBoardName MyBoardFamilyName" $dtb / compatible
     run_fdtget_test "77 121 66 111 \
 97 114 100 78 97 109 101 0 77 121 66 111 97 114 100 70 97 109 105 \
-108 121 78 97 109 101 0" $dtb / compatible
+108 121 78 97 109 101 0" -t bu $dtb / compatible
     run_fdtget_test "MyBoardName MyBoardFamilyName" -t s $dtb / compatible
     run_fdtget_test 32768 $dtb /cpus/PowerPC,970@1 d-cache-size
     run_fdtget_test 8000 -tx $dtb /cpus/PowerPC,970@1 d-cache-size

util.h

@@ -57,12 +57,14 @@ extern char *xstrdup(const char *s);
 extern char *join_path(const char *path, const char *name);
 
 /**
- * Check a string of a given length to see if it is all printable and
- * has a valid terminator.
+ * Check a property of a given length to see if it is all printable and
+ * has a valid terminator. The property can contain either a single string,
+ * or multiple strings each of non-zero length.
  *
  * @param data	The string to check
  * @param len	The string length including terminator
- * @return 1 if a valid printable string, 0 if not */
+ * @return 1 if a valid printable string, 0 if not
+ */
 int util_is_printable_string(const void *data, int len);
 
 /*