staging: vchiq: Fix an uninitialized variable

Smatch complains that "userdata" can be passed to vchiq_bulk_transfer()
without being initialized.  This leads to a potential information leak
later on.

Fixes: a4367cd2 ("staging: vchiq: convert compat bulk transfer")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lore.kernel.org/r/20200930123036.GC4282@kadam


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>