staging/bcm: add sparse annotations

This marks up the code where sparse complains in most cases.
Most of the changes are in the ioctl handling code, which
gets __user annotations, finding one unchecked user access.

The rest is mostly about marking functions static when they
are only used in one file.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>