Consistently use xrealloc instead of realloc

fdtput.c:
Replace the remaining call to realloc by xrealloc.
Some redundant lines in encode_value can be saved.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
diff --git a/fdtput.c b/fdtput.c
index 5226a4e..2a8d674 100644
--- a/fdtput.c
+++ b/fdtput.c
@@ -96,12 +96,7 @@
 		/* enlarge our value buffer by a suitable margin if needed */
 		if (upto + len > value_size) {
 			value_size = (upto + len) + 500;
-			value = realloc(value, value_size);
-			if (!value) {
-				fprintf(stderr, "Out of mmory: cannot alloc "
-					"%d bytes\n", value_size);
-				return -1;
-			}
+			value = xrealloc(value, value_size);
 		}
 
 		ptr = value + upto;