scripts/qemu.py: allow arches use KVM for their 32bit cousins

A lot of architectures can run their 32 bit cousins on KVM so the
kvm_available function needs to be a little less restricting when
deciding if KVM is available.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>

scripts/qemu.py

@@ -25,9 +25,17 @@ import tempfile
 
 LOG = logging.getLogger(__name__)
 
+# Mapping host architecture to any additional architectures it can
+# support which often includes its 32 bit cousin.
+ADDITIONAL_ARCHES = {
+    "x86_64" : "i386",
+    "aarch64" : "armhf"
+}
 
 def kvm_available(target_arch=None):
-    if target_arch and target_arch != os.uname()[4]:
+    host_arch = os.uname()[4]
+    if target_arch and target_arch != host_arch:
+        if target_arch != ADDITIONAL_ARCHES.get(host_arch):
             return False
     return os.access("/dev/kvm", os.R_OK | os.W_OK)