serial: msm_geni_serial: Check for dev_port->is_console flag for cosole

If console is disabled with below kernel cmdline arguments
"console=null earlycon=null androidboot.console=null" cons->name
will be set to null and cons->index pointer will not updated for
console. Hence uart_console(uport) check will fail, poxy vote
added by common driver probe on behalf of earlycon won't be
removed. This will not allow device to enter to enter sleep.

Fix this by replacing uart_console(uport)check with dev_port->console
check in probe so that it will remove vote during real console probe
after uart_add_one_port.

Change-Id: If41f588c10546abef247b55d3cd3a1f3e80cafe4
Signed-off-by: Chandana Kishori Chiluveru <cchiluve@codeaurora.org>