If an error occurs after request_mem_region(), a corresponding
release_mem_region() should be called, as already done in the remove
function.

Fixes: 1da177e4 ("Linux-2.6.12-rc2")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Helge Deller <deller@gmx.de>