m68k: Remove PCI and USB from config file

None of the ColdFire boards that we currently support has a PCI or
USB bus (and AFAIK the upcoming q800 machine does not support PCI
and USB either), so we do not need these settings the config file.
Signed-off-by: NThomas Huth <huth@tuxfamily.org>
Message-Id: <20170106083956.53d08923@thl530>
Signed-off-by: NLaurent Vivier <laurent@vivier.eu>

default-configs/m68k-softmmu.mak

 # Default configuration for m68k-softmmu
 
-include pci.mak
-include usb.mak
 CONFIG_COLDFIRE=y
 CONFIG_PTIMER=y