soc: qcom: spcom: create control channel

For commands that don't required SPU communication (is-link-up and
create channel), instead of using sp_kernel channel (the one used for
application loading) use /dev/spcom control channel.

Change-Id: I6e66949f7eb4ef9822b0b5ab37e9146c7ce23ab3
Signed-off-by: Kineret Berger <kberger@codeaurora.org>
Signed-off-by: Konstantin Dorfman <kdorfman@codeaurora.org>