staging: vchiq_core: introduce service skip

In case there is no service pointer provided, we can skip these polling.
Use a goto to reduce the indentation, which is necessary for the following
patches. Btw fix the brace alignment of the loops.

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Link: https://lore.kernel.org/r/1618164700-21150-6-git-send-email-stefan.wahren@i2se.com


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