aoe: remove redundant assignment on variable n

aoe: remove redundant assignment on variable n

The variable n is being bit-wise or'd with a value and reassigned
before being returned. The update of n is redundant, replace
the |= operator with | instead. Cleans up clang scan warning:

drivers/block/aoe/aoecmd.c:125:9: warning: Although the value stored
to 'n' is used in the enclosing expression, the value is never
actually read from 'n' [deadcode.DeadStores]

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Link: https://lore.kernel.org/r/20220113000545.1307091-1-colin.i.king@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>