sb/amd/cs5536: Remove includes of C files

The romstage for CS5536 platforms were including early_smbus.c and
early_setup.c.  Build these into romstage from the makefile, and remove
the #includes.

Add a Kconfig option for platforms that do not use the
early smbus code.

Change-Id: I2e6a9cd859292b4dd4720b547d1ff0bbb6c319cf
Signed-off-by: Martin Roth <martinroth@google.com>
Reviewed-on: https://review.coreboot.org/20607
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Patrick Georgi <pgeorgi@google.com>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>

src/mainboard/iei/pcisa-lx-800-r10/romstage.c

@@ -26,8 +26,6 @@
 #include <cpu/amd/lxdef.h>
 #include <southbridge/amd/cs5536/cs5536.h>
 #include <spd.h>
-#include "southbridge/amd/cs5536/early_smbus.c"
-#include "southbridge/amd/cs5536/early_setup.c"
 #include <superio/winbond/common/winbond.h>
 #include <superio/winbond/w83627hf/w83627hf.h>
 #include <northbridge/amd/lx/raminit.h>

src/mainboard/iei/pm-lx-800-r11/romstage.c

@@ -25,8 +25,6 @@
 #include <cpu/x86/msr.h>
 #include <cpu/amd/lxdef.h>
 #include <southbridge/amd/cs5536/cs5536.h>
-#include <southbridge/amd/cs5536/early_smbus.c>
-#include <southbridge/amd/cs5536/early_setup.c>
 #include <superio/winbond/common/winbond.h>
 #include <superio/winbond/w83627ehg/w83627ehg.h>
 #include <northbridge/amd/lx/raminit.h>

src/mainboard/iei/pm-lx2-800-r10/romstage.c

@@ -27,8 +27,6 @@
 #include <cpu/amd/car.h>
 #include <cpu/amd/lxdef.h>
 #include <southbridge/amd/cs5536/cs5536.h>
-#include <southbridge/amd/cs5536/early_smbus.c>
-#include <southbridge/amd/cs5536/early_setup.c>
 #include <superio/smsc/smscsuperio/smscsuperio.h>
 #include <northbridge/amd/lx/raminit.h>