Drop CONFIG_HAVE_BUS_CONFIG, clean up Kconfig

This patch is the beginning of a Kconfig cleanup series
- drop CONFIG_HAVE_BUS_CONFIG and add get_bus_conf.c if it
  exists in the mainboard directory
- drop duplicate ACPI_SSDTX_NUM from mainboard Kconfig
  if it only defines the defaul value of 0
- Add mptable.c, fadt.c, reset.c and ssdtX.asl when they
  exist, not based on some Kconfig magic

Signed-off-by: Stefan Reinauer <reinauer@google.com>

Change-Id: Ia14a7116dad6a724af7e531920fee9a51fd0b200
Reviewed-on: http://review.coreboot.org/1832
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>

src/mainboard/sunw/ultra40/Kconfig

@@ -9,7 +9,6 @@ config BOARD_SPECIFIC_OPTIONS # dummy
 	select SOUTHBRIDGE_NVIDIA_CK804
 	select SUPERIO_SMSC_LPC47M10X
 	select HAVE_OPTION_TABLE
-	select HAVE_BUS_CONFIG
 	select HAVE_PIRQ_TABLE
 	select HAVE_MP_TABLE
 	select BOARD_ROMSIZE_KB_1024