megasas: disable due to build breakage

The Buildbot has detected a new failure on builder default_i386_rhel61 while
building qemu.

Full details are available at:
 http://buildbot.b1-systems.de/qemu/builders/default_i386_rhel61/builds/304

The proper fix is non-trivial so let's disable the build by default until it's
fixed properly.
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

default-configs/pci.mak

@@ -10,7 +10,6 @@ CONFIG_EEPRO100_PCI=y
 CONFIG_PCNET_PCI=y
 CONFIG_PCNET_COMMON=y
 CONFIG_LSI_SCSI_PCI=y
-CONFIG_MEGASAS_SCSI_PCI=y
 CONFIG_RTL8139_PCI=y
 CONFIG_E1000_PCI=y
 CONFIG_IDE_CORE=y