Work around architectures having statfs.f_type defined as long

Work around architectures having statfs.f_type defined as long

Having RAMFS_MAGIC defined as 0x858458f6 causing problems when trying
to compare it directly against statfs.f_type being cast from long to
unsigned long.

This hack is extremly ugly, but it should at least do the right thing
for every situation.

Thanks to Arnd Bergmann for suggesting the fix.

Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>