staging: vchiq_arm: fix open/release cdev functions

Both functions checked the minor number of the cdev prior running the
code. This was useless since the number of devices is already limited by
alloc_chrdev_region.

This removes the check and reindents the code where relevant.

Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
Acked-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>