mtd, nand: Move common functions from cmd_nand.c to common place

Move common functions from cmd_nand.c (for calculating offset
and size from cmdline paramter) to common place, so they could
used from other commands which use mtd partitions.

For onenand the arg_off_size() is left in common/cmd_onenand.c.
It should use now the common arg_off() function, but as I could
not test onenand I let it there ...

Signed-off-by: Heiko Schocher <hs@denx.de>
Acked-by: Scott Wood <scottwood@freescale.com>
Reviewed-by: Jagannadh Teki <jteki@openedev.com>
diff --git a/common/cmd_test.c b/common/cmd_test.c
index c93fe78..7285f75 100644
--- a/common/cmd_test.c
+++ b/common/cmd_test.c
@@ -5,15 +5,6 @@
  * SPDX-License-Identifier:	GPL-2.0+
  */
 
-/*
- * Define _STDBOOL_H here to avoid macro expansion of true and false.
- * If the future code requires macro true or false, remove this define
- * and undef true and false before U_BOOT_CMD. This define and comment
- * shall be removed if change to U_BOOT_CMD is made to take string
- * instead of stringifying it.
- */
-#define _STDBOOL_H
-
 #include <common.h>
 #include <command.h>
 #include <fs.h>
@@ -191,6 +182,9 @@
 	return expr;
 }
 
+#undef true
+#undef false
+
 U_BOOT_CMD(
 	test,	CONFIG_SYS_MAXARGS,	1,	do_test,
 	"minimal test like /bin/sh",