cmd_zfs: use common get_device_and_partition function

Convert zfsload and zfsls to use common device and partition parsing
function. With the common function "dev:part" can come from the
environment and a '-' can be used in that case.

Signed-off-by: Rob Herring <rob.herring@calxeda.com>
diff --git a/include/zfs_common.h b/include/zfs_common.h
index 628231e..3bd575e 100644
--- a/include/zfs_common.h
+++ b/include/zfs_common.h
@@ -66,9 +66,6 @@
 	block_dev_desc_t *dev_desc;
 };
 
-
-extern block_dev_desc_t *zfs_dev_desc;
-
 struct device_s {
 	uint64_t part_length;
 };
@@ -101,7 +98,7 @@
 int zfs_ls(device_t dev, const char *path,
 		   int (*hook) (const char *, const struct zfs_dirhook_info *));
 int zfs_devread(int sector, int byte_offset, int byte_len, char *buf);
-int zfs_set_blk_dev(block_dev_desc_t *rbdd, int part);
+void zfs_set_blk_dev(block_dev_desc_t *rbdd, disk_partition_t *info);
 void zfs_unmount(struct zfs_data *data);
 int lzjb_decompress(void *, void *, uint32_t, uint32_t);
 #endif