astlpc: abstract hardware interactions to allow a non-fileio-based implementation

Currently, the astlpc binding assumes a particular method of access to
the KCS and LPC interfaces, using reads and writes to a pair of Linux
devices.

We want to be able to use the astlpc binding in different environments,
possibly not backed by file IO. This change adds an interface to provide
custom operations to read and write the KCS and LPC state.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Change-Id: I3e403a025760657a7264098f5486f046e3ac436b
diff --git a/utils/mctp-demux-daemon.c b/utils/mctp-demux-daemon.c
index c8c1dff..f64f029 100644
--- a/utils/mctp-demux-daemon.c
+++ b/utils/mctp-demux-daemon.c
@@ -173,7 +173,7 @@
 		return -1;
 	}
 
-	astlpc = mctp_astlpc_init();
+	astlpc = mctp_astlpc_init_fileio();
 	if (!astlpc) {
 		warnx("could not initialise astlpc binding");
 		return -1;