btrfs: check-integrity: Fix returned errno codes
check-integrity is using -1 instead of the -ENOMEM defined macro to
specify that a buffer allocation failed. Since the error number is
propagated, the caller will get a -EPERM which is the wrong error
condition.
Also, the smatch tool complains with the following warnings:
btrfsic_process_superblock() warn: returning -1 instead of -ENOMEM is sloppy
btrfsic_read_block() warn: returning -1 instead of -ENOMEM is sloppy
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
Signed-off-by: David Sterba <dsterba@suse.com>