Staging: vc04_services: remove unused variables

the volatile fields of bcm2835_alsa_stream - control and status are not used.

$ grep bcm2835_alsa_stream
From the above command all instances we see that
all variables of 'bcm2835_alsa_stream' are declared as
'alsa_stream'

So search for 'control' wherever we have 'alsa_stream'

$ grep -l 'alsa_stream' | xargs grep "control"
The above command returns where we don't any usage of
'control' field. which means that there is no usage of
these fields.

similarly for 'status' we see no usages.

---
changes in v2:
more discriptive commit message.

 drivers/staging/vc04_services/bcm2835-audio/bcm2835.h | 2 --
 1 file changed, 2 deletions(-)

index 379604d..f1e43e4 100644
@@ -123,8 +123,6 @@ struct bcm2835_alsa_stream {
 	struct snd_pcm_indirect pcm_indirect;
 
 	spinlock_t lock;
-	volatile unsigned int control;
-	volatile unsigned int status;
 
 	int open;
 	int running;

2.7.4