staging: vchiq_core: Reduce the memdump size

This reduces the memory dump size to a sufficient value of 16 bytes.

Signed-off-by: Phil Elwell <phil@raspberrypi.org>
Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>