Memory footprint optimizations

As suggested by Wolfgang Denk:
- image printing functions:
  - remove wrappers
  - remove indentation prefix from functions' signatures
- merge getenv_verify and getenv_autostart into one parametrized function

Signed-off-by: Bartlomiej Sieka <tur@semihalf.com>
diff --git a/common/cmd_bootm.c b/common/cmd_bootm.c
index ae9c21b..44f6b9f 100644
--- a/common/cmd_bootm.c
+++ b/common/cmd_bootm.c
@@ -132,8 +132,8 @@
 	struct lmb lmb;
 
 	memset ((void *)&images, 0, sizeof (images));
-	images.verify = getenv_verify();
-	images.autostart = getenv_autostart();
+	images.verify = getenv_yesno ("verify");
+	images.autostart = getenv_yesno ("autostart");
 	images.lmb = &lmb;
 
 	lmb_init(&lmb);