Dynamic debug: allow simple quoting of words

Allow simple quoting of words in the dynamic debug control language.

This allows more natural specification when using the control language
to match against printk formats, e.g

#echo -n 'format "Setting node for non-present cpu" +p' >
	/mnt/debugfs/dynamic_debug/control

instead of

#echo -n 'format Setting\040node\040for\040non-present\040cpu +p' >
	/mnt/debugfs/dynamic_debug/control

Adjust the dynamic debug documention to describe that and provide a
new example.  Adjust the existing examples in the documentation to
reflect the current whitespace escaping behaviour when reading the
control file.  Fix some minor documentation trailing whitespace.

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