tools: Fix ifdef for aarch64 that should include also arm

Commit 56a7aaa16b introduced some SVE related code that is protected by
'#if defined(__aarch64__)', the issue is that this doesn't take into
consideration when the toolstack is compiled for an arm32 Dom0 running on
an arm64 platform, it should be able to create SVE enabled guests but with
the current code it's not.

So fix the issue by compiling the code when the toolstack is compiled for
both arm32 and arm64.

Fixes: 56a7aaa16b ("tools: add physinfo arch_capabilities handling for Arm")
Signed-off-by: Luca Fancellu <luca.fancellu@arm.com>
Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
Acked-by: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com>

tools/python/xen/lowlevel/xc/xc.c

@@ -911,7 +911,7 @@ static PyObject *pyxc_physinfo(XcObject *self)
                            "hw_caps",          cpu_cap,
                            "virt_caps",        virt_caps);
 
-#if defined(__aarch64__)
+#if defined(__arm__) || defined(__aarch64__)
     if ( objret ) {
         unsigned int sve_vl_bits;
         PyObject *py_arm_sve_vl;