staging: vchiq: convert to use a miscdevice

staging: vchiq: convert to use a miscdevice

Using a struct class, a cdev, and another device just for a single minor
device is total overkill.  Just use a dynamic misc device instead,
saving lots of logic and memory.

Cc: Nicolas Saenz Julienne <nsaenz@kernel.org>
Cc: Stefan Wahren <stefan.wahren@i2se.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Ojaswin Mujoo <ojaswin98@gmail.com>
Cc: Phil Elwell <phil@raspberrypi.com>
Cc: bcm-kernel-feedback-list@broadcom.com
Cc: linux-rpi-kernel@lists.infradead.org
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20210907115045.2206083-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>