staging: vc04_services: Remove unnecessary braces

Remove unnecessary braces for single statements also declare a local
variable "platform_state" of type "struct vchiq_2835_state", to
avoid the multiple cast.

Signed-off-by: Mihaela Muraru <mihaela.muraru21@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>