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_elf.c b/common/cmd_elf.c
index 27a4b73..19e1249 100644
--- a/common/cmd_elf.c
+++ b/common/cmd_elf.c
@@ -310,12 +310,12 @@
 /* ====================================================================== */
 U_BOOT_CMD(
 	bootelf,      2,      0,      do_bootelf,
-	"bootelf - Boot from an ELF image in memory\n",
+	"Boot from an ELF image in memory",
 	" [address] - load address of ELF image.\n"
 );
 
 U_BOOT_CMD(
 	bootvx,      2,      0,      do_bootvx,
-	"bootvx  - Boot vxWorks from an ELF image\n",
+	"Boot vxWorks from an ELF image",
 	" [address] - load address of vxWorks ELF image.\n"
 );