This makes the following do the expected thing:

	barebox@barebox sandbox:/ ls -l lala
	-rwxrwxrwx              4 lala
	barebox@barebox sandbox:/ mw -d lala 72 0

Without this patch mw dies with

	lseek: Invalid argument

memset, memcpy and probably others benefit in the same way.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>