staging: bcm2835-camera: Add multiple include protection

mmal-parameters.h didn't have the normal

...

protection to stop it being included multiple times.  Add it.

Signed-off-by: Dave Stevenson <dave.stevenson@raspberrypi.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>