BluetoothMidi: ignore reserved bit in header

The BLE-MIDI spec defines bit 6 as reserved.
The decoder was checking to make sure it was zero.
But that would prevent it from being used in the future.
So now it ignores the reserved bit.

Bug: 149927520
Test: atest BluetoothMidiTests
Change-Id: Ibd2054c4dbf01941da56727b49dec23dc65088c0

media/packages/BluetoothMidiService/src/com/android/bluetoothmidiservice/BluetoothPacketDecoder.java

@@ -70,7 +70,9 @@ public class BluetoothPacketDecoder extends PacketDecoder {
         }
 
         byte header = buffer[0];
-        if ((header & 0xC0) != 0x80) {
+        // Check for the header bit 7.
+        // Ignore the reserved bit 6.
+        if ((header & 0x80) != 0x80) {
             Log.e(TAG, "packet does not start with header");
             return;
         }