staging: vchiq: convert compat bulk transfer

staging: vchiq: convert compat bulk transfer

Split out the ioctl implementation for VCHIQ_IOC_QUEUE_BULK_TRANSMIT
into a separate function so it can be shared with the compat
implementation.

Here, the input data is converted separately in the compat
handler, while the output data is passed as a __user pointer
to thec vchiq_queue_bulk_transfer->mode word that is
compatible.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20200918095441.1446041-5-arnd@arndb.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>