staging: unisys: refactor ULTRA_channel_client_acquire_os()

Remove the unnecessary macro ULTRA_CHANNEL_CLIENT_ACQUIRE_OS for calling
the function, and rename the function to
spar_channel_client_acquire_os(). Get rid of unneeded parameters logCtx,
file, and line, 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>