staging: vchiq_arm: rework close/remove_service IOCTLS

The implementation of both IOCTLS was the same except for one function
call. This joins both implementations and updates the code to avoid
unneeded indentations.

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>