linux-yocto/4.12: common-pc*: enable X2APIC by default

linux-yocto/4.12: common-pc*: enable X2APIC by default

Enabling CONFIG_X86_X2APIC=y by default for common-pc* (and hence
qemux86*) to work around interrupt delivery issues when running on some
host kernels.

There's little overhead with this, and no impact to non x2apic
platforms, so we enable it for all builds.

Signed-off-by: Bruce Ashfield <bruce.ashfield@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>