media: av7110: coding style fixes: sizeof

This patch fixes the following checkpatch warnings:

WARNING:SIZEOF_PARENTHESIS: sizeof d should be sizeof(d)
WARNING:SIZEOF_PARENTHESIS: sizeof f->fmt.sliced should be sizeof(f->fmt.sliced)
WARNING:CONST_STRUCT: struct dvb_frontend_ops should normally be const
CHECK:ALLOC_SIZEOF_STRUCT: Prefer kzalloc(sizeof(*av7110)...) over kzalloc(sizeof(struct av7110)...)

Signed-off-by: Stefan Herdler <herdler@nurfuerspam.de>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>