Fix incorrect use of getenv() before relocation

A large number of boards incorrectly used getenv() in their board init
code running before relocation.  In some cases this caused U-Boot to
hang when certain environment variables grew too long.
Fix the code to use getenv_r().

Signed-off-by: Wolfgang Denk <wd@denx.de>
Cc: Stefan Roese <sr@denx.de>
Cc: The LEOX team <team@leox.org>
Cc: Michael Schwingen <michael@schwingen.org>
Cc: Georg Schardt <schardt@team-ctech.de>
Cc: Werner Pfister <Pfister_Werner@intercontrol.de>
Cc: Dirk Eibach <eibach@gdsys.de>
Cc: Peter De Schrijver <p2@mind.be>
Cc: John Zhan <zhanz@sinovee.com>
Cc: Rishi Bhattacharya <rishi@ti.com>
Cc: Peter Tyser <ptyser@xes-inc.com>
diff --git a/board/avnet/fx12mm/fx12mm.c b/board/avnet/fx12mm/fx12mm.c
index e671a7b..c975efa 100644
--- a/board/avnet/fx12mm/fx12mm.c
+++ b/board/avnet/fx12mm/fx12mm.c
@@ -32,20 +32,19 @@
 
 int checkboard(void)
 {
-	char tmp[64];
-	char *s, *e;
-	int i = getenv_f("serial", tmp, sizeof(tmp));
+	char buf[64];
+	int i;
+	int l = getenv_f("serial#", buf, sizeof(buf));
 
-	if (i < 0) {
+	if (l < 0) {
 		printf("Avnet Virtex4 FX12 with no serial #");
 	} else {
-		for (e = tmp; *e; ++e) {
-			if (*e == ' ')
-				break;
-		}
 		printf("Avnet Virtex4 FX12 Minimodul # ");
-		for (s = tmp; s < e; ++s)
-			putc(*s);
+		for (i = 0; i < l; ++i) {
+			if (buf[i] == ' ')
+				break;
+			putc(buf[i]);
+		}
 	}
 	putc('\n');
 	return 0;