Command usage cleanup

Remove command name from all command "usage" fields and update
common/command.c to display "name - usage" instead of
just "usage". Also remove newlines from command usage fields.

Signed-off-by: Peter Tyser <ptyser@xes-inc.com>
diff --git a/common/cmd_bootldr.c b/common/cmd_bootldr.c
index e6474aa..b525f0d 100644
--- a/common/cmd_bootldr.c
+++ b/common/cmd_bootldr.c
@@ -59,6 +59,6 @@
 }
 
 U_BOOT_CMD(bootldr, 2, 0, do_bootldr,
-	"bootldr - boot ldr image from memory\n",
+	"boot ldr image from memory",
 	"[addr]\n"
 	"    - boot ldr image stored in memory\n");