vt: drop redundant might_sleep() in do_con_write()

The might_sleep() in do_con_write() is redundant because console_lock()
already contains might_sleep().  Remove it.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20200224073450.292892-1-ebiggers@kernel.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>