Set correct obmc-host-ipmi-hw for s2600wf

s2600wf uses kcs instead of bt

Tested By:
With change change, the below bitbake message will disappear:
NOTE: Multiple providers are available for runtime virtual-obmc-host-ipmi-hw (phosphor-ipmi-bt, phosphor-ipmi-hw-example, phosphor-ipmi-kcs)
Consider defining a PREFERRED_RPROVIDER entry to match virtual-obmc-host-ipmi-hw

Change-Id: Ibfeedb21de1e054f42d7f0775c57383736ae2836
Signed-off-by: Yong Li <yong.b.li@linux.intel.com>
diff --git a/conf/machine/include/intel.inc b/conf/machine/include/intel.inc
index 0884294..db6b0c1 100644
--- a/conf/machine/include/intel.inc
+++ b/conf/machine/include/intel.inc
@@ -17,5 +17,5 @@
 PREFERRED_PROVIDER_virtual/obmc-system-mgmt = "packagegroup-intel-apps"
 PREFERRED_PROVIDER_virtual/obmc-host-ctl ?= "obmc-op-control-host"
 PREFERRED_PROVIDER_virtual/obmc-inventory-data ?= "${VIRTUAL-RUNTIME_skeleton_workbook}"
-PREFERRED_PROVIDER_virtual/obmc-host-ipmi-hw = ""
+PREFERRED_PROVIDER_virtual/obmc-host-ipmi-hw = "phosphor-ipmi-kcs"
 #PREFERRED_PROVIDER_virtual/obmc-gpio-monitor ?= "phosphor-gpio-monitor"