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/board/prodrive/pdnb3/pdnb3.c b/board/prodrive/pdnb3/pdnb3.c
index 9b87f6a..8777284 100644
--- a/board/prodrive/pdnb3/pdnb3.c
+++ b/board/prodrive/pdnb3/pdnb3.c
@@ -227,7 +227,7 @@
 
 U_BOOT_CMD(
 	fpga,     2,     0,      do_fpga,
-	"fpga    - boot FPGA\n",
+	"boot FPGA",
 	"address size\n    - boot FPGA with gzipped image at <address>\n"
 );