Enable multiple EDR connection in Android.

Enable multiple EDR connection in Android.

Using Available API before using blocking EDR read function.
Bluetooth read function is a blocking function which makes other connection to wait.
So added checking the packet availability before making blocking read.

Change-Id: I794a4010ae6ad3e21c63f3a9e3e9d3fc0d89cad5
Signed-off-by: Jaehong Jo <jaehong.jo@samsung.com>
Reviewed-on: https://gerrit.iotivity.org/gerrit/4277
Tested-by: jenkins-iotivity <jenkins-iotivity@opendaylight.org>
Reviewed-by: Jon A. Cruz <jonc@osg.samsung.com>