a3m071: Make spl_start_uboot test like getenv_yesno does

This change makes the behaviour slightly more rebust and will match
other implementations which can use getenv_yesno directly.
Acked-by: NStefan Roese <sr@denx.de>
Signed-off-by: NTom Rini <trini@ti.com>

board/a3m071/a3m071.c

@@ -412,7 +412,8 @@ int spl_start_uboot(void)
 
 	env_init();
 	getenv_f("boot_os", s, sizeof(s));
-	if ((s != NULL) && (strcmp(s, "yes") == 0))
+	if ((s != NULL) && (*s == '1' || *s == 'y' || *s == 'Y' ||
+			    *s == 't' || *s == 'T'))
 		return 0;
 
 	return 1;