fix configuring kvm probe when using --kerneldir (Christian Ehrhardt)

fix configuring kvm probe when using --kerneldir (Christian Ehrhardt)

There is already a variable kvm_cflags which gets the path of the kernel
includes when using --kerneldir. But eventually with newer kernels we all will
need arch/$arch/include too (my case was a incldue of asm/kvm.h which was not
found anymore). Headers in a full kernel source are not flattened to
one arch like they are if e.g. installed kernel headers are used.

To fix that, the includes added to cflags depending on --kerneldir should also
contian the arch includes. The patch adds a special check for x86 because its
source layout recently changed, all others directly use arch/$cpu/include if
existent.

Signed-off-by: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@6263 c046a42c-6fe2-441c-8c8c-71466251a162