nvidia/ck804: Fix FTBFS with AMD Family 10h systems

The build failure stems from a missing function being called via a chain
including setup_ss_table(), set_ht_link_ck804(), and
st_ht_link_buffer_counts_chain(); the latter function is only available
in the AMD K8 code.

It appears that a bunch of K8-specific code snuck into the CK804 and MCP55
southbridge code in GIT commit 968bbe89 and GIT commit d4b278c0.

Change-Id: I85d005edba44c503c49917d4b928e5c9c5900059
Signed-off-by: Timothy Pearson <tpearson@raptorengineeringinc.com>
Reviewed-on: http://review.coreboot.org/8269
Tested-by: build bot (Jenkins)
Reviewed-by: Jonathan A. Kollasch <jakllsch@kollasch.net>
Reviewed-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>

src/southbridge/nvidia/ck804/early_setup_car.c

@@ -1,6 +1,8 @@
 /*
  * This file is part of the coreboot project.
  *
+ * Copyright (C) 2015 Timothy Pearson <tpearson@raptorengineeringinc.com>, Raptor Engineering
+ *
  * Copyright (C) 2004 Tyan Computer
  * Written by Yinghai Lu <yhlu@tyan.com> for Tyan Computer.
  *
@@ -18,6 +20,11 @@
  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
+#if !IS_ENABLED(CONFIG_NORTHBRIDGE_AMD_AMDK8)
+/* Someone messed up and snuck in some K8-specific code */
+static int  set_ht_link_buffer_counts_chain(uint8_t ht_c_num, unsigned vendorid, unsigned val) { return 0; /* stub */};
+#endif
+
 static int set_ht_link_ck804(u8 ht_c_num)
 {
 	unsigned vendorid = 0x10de;