Use dev_* style print when struct device is available.

Also combine previously line broken user-visible strings as per
Documentation/CodingStyle:

"However, never break user-visible strings such as printk messages,
because that breaks the ability to grep for them."
Signed-off-by: Ira Weiny <ira.weiny@intel.com>

[ Remove PFX so the patch actually builds.  - Roland ]
Signed-off-by: Roland Dreier <roland@purestorage.com>