phodevi: check if test supports extra host arch

Marking test as compatible if optional HOST_EXTRA_COMPATIBLE_ARCH
environmental variable is matching one of the supported architectures.

Signed-off-by: Ettore Chimenti <ettore.chimenti@linaro.org>

pts-core/objects/phodevi/phodevi.php

@@ -836,7 +836,7 @@ class phodevi extends phodevi_base
 		{
 			$this_arch = 'x86';
 		}
-		if(!in_array($this_arch, $check_against))
+		if(!in_array($this_arch, $check_against) && !in_array(pts_env::read('HOST_EXTRA_COMPATIBLE_ARCH'), $check_against))
 		{
 			$compatible = false;
 		}