staging: unisys: refactor ULTRA_channel_client_release_os()

Remove the unnecessary macro ULTRA_CHANNEL_CLIENT_RELEASE_OS(), rename
the function to spar_channel_client_release_os(), fix references to the
macro to call the function directly instead, remove the unnecessary
logCtx, file, and line parameters, and fix CamelCase names:

pChannel => ch
chanId => id
pChan => hdr

Signed-off-by: Benjamin Romer <benjamin.romer@unisys.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>