drm/radeon/atom: Send out the full AUX address

AUX addresses are 20 bits long. Send out the entire address instead of
just the low 16 bits.

Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

drivers/gpu/drm/radeon/atombios_dp.c

@@ -171,8 +171,9 @@ radeon_dp_aux_transfer_atom(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
 		return -E2BIG;
 
 	tx_buf[0] = msg->address & 0xff;
-	tx_buf[1] = msg->address >> 8;
-	tx_buf[2] = msg->request << 4;
+	tx_buf[1] = (msg->address >> 8) & 0xff;
+	tx_buf[2] = (msg->request << 4) |
+		((msg->address >> 16) & 0xf);
 	tx_buf[3] = msg->size ? (msg->size - 1) : 0;
 
 	switch (msg->request & ~DP_AUX_I2C_MOT) {