uart: fix uart_opal_flush to take console lock over uart_con_flush
uart: fix uart_opal_flush to take console lock over uart_con_flush

Cc: Russell Currey <b5ebcef270cdc73fa0593440445c07a93ae1bccb@russell.cc>
Signed-off-by: Nicholas Piggin <24829078df5003d9dd1dd871ca2aeb0b1cf95ef4@gmail.com>
Reviewed-by: Russell Currey <b5ebcef270cdc73fa0593440445c07a93ae1bccb@russell.cc>
Signed-off-by: Stewart Smith <ec31ab75ddf977353c8f660f92ea8b23f64aef25@linux.ibm.com>

qemu/skiboot,qemu/skiboot,shenki/skiboot,qemu/skiboot,open-power/skiboot,legoater/skiboot,shenki/skiboot,legoater/skiboot,legoater/skiboot,open-power/skiboot,shenki/skiboot,open-power/skiboot,legoater/skiboot,stewart-ibm/skiboot,stewart-ibm/skiboot,stewart-ibm/skiboot,qemu/skiboot,open-power/skiboot,open-power/skiboot,shenki/skiboot,qemu/skiboot,shenki/skiboot,legoater/skiboot