staging: vchiq: rework compat handling

staging: vchiq: rework compat handling

The compat handlers for VCHIQ_IOC_QUEUE_MESSAGE32 and
VCHIQ_IOC_GET_CONFIG32 can simply call the underlying implementations
that are already separate functions rather than using copy_in_user to
simulate the native 64-bit interface for the full ioctl handler.

vchiq_ioc_queue_message gets a small update to the calling
conventions to simplify the compat version by directly
returning a normal errno value.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20200918095441.1446041-2-arnd@arndb.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>