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_sf.c b/common/cmd_sf.c
index 6dc522d..6a60b16 100644
--- a/common/cmd_sf.c
+++ b/common/cmd_sf.c
@@ -181,7 +181,7 @@
 
 U_BOOT_CMD(
 	sf,	5,	1,	do_spi_flash,
-	"sf	- SPI flash sub-system\n",
+	"SPI flash sub-system",
 	"probe [bus:]cs [hz] [mode]	- init flash device on given SPI bus\n"
 	"				  and chip select\n"
 	"sf read addr offset len 	- read `len' bytes starting at\n"