drivers: remove snapdragon_pwm_out

- it would need to be refactored to use mixer_module
- rather than having a separate driver it should use linux_pwm_out

Tools/uorb_graph/create.py

@@ -223,7 +223,6 @@ class Graph(object):
     ('listener', r'.*', None, r'^(id)$'),
     ('logger', r'.*', None, r'^(topic|sub\.metadata|_polling_topic_meta)$'),
 
-    ('snapdragon_pwm_out', r'.*', r'\b_controls_topics\[[0-9]\]=([^,)]+)', r'^_controls_topics\[i\]$'),
     ]
         special_cases_sub = [(a, re.compile(b), re.compile(c) if c is not None else None, re.compile(d))
                                    for a,b,c,d in special_cases_sub]