drbd: get rid of drbd_bcast_ee, it is of no use anymore

This function was used to broadcast the (leading part of the)
bio payload in case we see a data integrity error.  It could be received
from userland with the drbdsetup events subcommand,
to have a peek into the payload that caused the checksum mismatch,
and guess from there what may have caused the mismatch,
mainly to guess wether it was modification of in-flight data,
or data corruption by broken hardware or software bugs.

Meanwhile we support bios that are larger than the maximum payload a
netlink datagram can carry.
And we have means to reliably detect modification of in-flight data by
calculating, and comparing, the checksum before and after sendmsg.
There is no need to carry this around anymore.
Signed-off-by: NPhilipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: NLars Ellenberg <lars.ellenberg@linbit.com>

drivers/block/drbd/drbd_receiver.c

@@ -1353,8 +1353,6 @@ read_in_block(struct drbd_conf *mdev, u64 id, sector_t sector,
 		if (memcmp(dig_in, dig_vv, dgs)) {
 			dev_err(DEV, "Digest integrity check FAILED: %llus +%u\n",
 				(unsigned long long)sector, data_size);
-			drbd_bcast_ee(mdev, "digest failed",
-					dgs, dig_in, dig_vv, peer_req);
 			drbd_free_ee(mdev, peer_req);
 			return NULL;
 		}