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/amirix/ap1000/powerspan.c b/board/amirix/ap1000/powerspan.c
index f048155..f727061 100644
--- a/board/amirix/ap1000/powerspan.c
+++ b/board/amirix/ap1000/powerspan.c
@@ -478,7 +478,7 @@
 }
 
 U_BOOT_CMD (eeprom, 4, 0, do_eeprom,
-	    "eeprom  - read/write/copy to/from the PowerSpan II eeprom\n",
+	    "read/write/copy to/from the PowerSpan II eeprom",
 	    "eeprom r OFF [NUM]\n"
 	    "    - read NUM words starting at OFF\n"
 	    "eeprom w OFF VAL\n"