staging: vc04_services: rename structures bm2835_mmal_dev and bm2835_mmal_v4l2_ctrl

staging: vc04_services: rename structures bm2835_mmal_dev and bm2835_mmal_v4l2_ctrl

In the kernel, all names related to the chip BCM2835 are always named
bcm2835_*. To avoid confusion, and to make things more consistent,
rename the structures bm2835_mmal_dev and bm2835_mmal_v4l2_ctrl
accordingly.

While at it, one realignment was made to improve readability.

Suggested-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Gaston Gonzalez <gascoar@gmail.com>
Link: https://lore.kernel.org/r/a893f24fc5ee6c276ea982f141b42ec0a00d7194.1641414449.git.gascoar@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>