mei: fix incorrect logical operator in if statement

The current expression using the || operator is always true because
dev->dev_state cannot be equal to two different values at the same time.
Fix this by replacing the || with &&.

Detected by CoverityScan, CID#1463042 ("Constant expression result")

Fixes: 8d52af67 ("mei: speed up the power down flow")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>