Driver core: remove pr_fmt() from dynamic_dev_dbg() printk

When pr_fmt() was added to the pr_debug() code, we added it not only to the
dynamic_pr_debug() function, but also to the dynamic_dev_dbg() funciton.
However, dev_dbg() doesn't make use of pr_fmt(), so neither should
dynamic_dev_dbg().

Signed-off-by: Jason Baron <jbaron@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>