Staging: pohmelfs: fix compile warning

A really trivial patch to solve a warning when compiling staging/pohmelfs

Signed-off-by: Javier Martinez Canillas <martinez.javier@gmail.com>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>