target.config: add device ID parameter for Android target
target.config: add device ID parameter for Android target

In case of multiple Android devices attached to the host, the user must
specify the device ID of the target (obtained running `adb devices` on the
host). Example:

  $ adb devices
  List of attached devices
  00b1346f0878ccb1        device

Signed-off-by: Michele Di Giorgio <99fd0b6f5a4e02a4022988691284da2a0299b046@arm.com>

credp/lisa,mdigiorgio/lisa,arnoldlu/lisa,JaviMerino/lisa,credp/lisa,credp/lisa,ARM-software/lisa,mdigiorgio/lisa,ARM-software/lisa,bjackman/lisa,ARM-software/lisa,joelagnel/lisa,credp/lisa,arnoldlu/lisa,bjackman/lisa,joelagnel/lisa,ARM-software/lisa