staging: vc04_services: Rename callback VCHI_CALLBACK_T to vchi_callback

Renames callback function pointer typedef VCHI_CALLBACK_T to
vchi_callback to better match kernel code style.

Signed-off-by: Jamal Shareef <jamal.k.shareef@gmail.com>
Link: https://lore.kernel.org/r/0b0f85060b38e6195fe2d58989621e7b09eafe51.1572994235.git.jamal.k.shareef@gmail.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>