Strictly speaking, lseek() doesn't return a detailed error code as its
return value and it can and should be obtained via 'errno'. In this
case this change also allows us to avoid potential problems from
downconverting 'loff_t' to 'int'.

Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>