V4L/DVB: drivers/media: Correct NULL test

In each case, the NULL test has been performed already.

A simplified version of the semantic match that finds this problem is as
follows: (http://coccinelle.lip6.fr/)

// <smpl>
@r@
expression *x;
expression e;
identifier l;
@@

if (x == NULL || ...) {
    ... when forall
    return ...; }
... when != goto l;
    when != x = e
    when != &x
*x == NULL
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

drivers/media/dvb/frontends/stv0900_core.c

@@ -1417,11 +1417,6 @@ static enum fe_stv0900_error stv0900_init_internal(struct dvb_frontend *fe,
 		return error;
 	}
 
-	if (state->internal == NULL) {
-		error = STV0900_INVALID_HANDLE;
-		return error;
-	}
-
 	intp = state->internal;
 
 	intp->demod_mode = p_init->demod_mode;

drivers/media/video/cpia.c

@@ -3737,9 +3737,6 @@ static int cpia_mmap(struct file *file, struct vm_area_struct *vma)
 	if (size > FRAME_NUM*CPIA_MAX_FRAME_SIZE)
 		return -EINVAL;
 
-	if (!cam || !cam->ops)
-		return -ENODEV;
-
 	/* make this _really_ smp-safe */
 	if (mutex_lock_interruptible(&cam->busy_lock))
 		return -EINTR;