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/tqc/tqm8272/tqm8272.c b/board/tqc/tqm8272/tqm8272.c
index 96ec078..9efb541 100644
--- a/board/tqc/tqm8272/tqm8272.c
+++ b/board/tqc/tqm8272/tqm8272.c
@@ -514,12 +514,16 @@
 static int dump_hwib(void)
 {
 	HWIB_INFO	*hw = &hwinf;
+	char buf[64];
+	int i = getenv_f("serial#", buf, sizeof(buf));
 	volatile immap_t *immr = (immap_t *)CONFIG_SYS_IMMR;
-	char *s = getenv("serial#");
+
+	if (i < 0)
+		buf[0] = '\0';
 
 	if (hw->OK) {
 		printf ("HWIB on %x\n", HWIB_INFO_START_ADDR);
-		printf ("serial : %s\n", s);
+		printf ("serial : %s\n", buf);
 		printf ("ethaddr: %s\n", hw->ethaddr);
 		printf ("FLASH	: %x nr:%d\n", hw->flash, hw->flash_nr);
 		printf ("RAM	: %x cs:%d\n", hw->ram, hw->ram_cs);