Made abi property common between Android and Linux devices

In both cases, the ABI is now obtained by executing "uname -m" on the
device and perfroming a mapping from the returned machine architecture
a known ABI. If no known ABI is found the architecture string itself is
returned.

wlauto/common/android/device.py

@@ -96,10 +96,6 @@ class AndroidDevice(BaseLinuxDevice):  # pylint: disable=W0223
                 self._is_rooted = False
         return self._is_rooted
 
-    @property
-    def abi(self):
-        return self.getprop()['ro.product.cpu.abi'].split('-')[0]
-
     @property
     def supported_eabi(self):
         props = self.getprop()