serial: omap: Remove unnecessary checks from suspend/resume

Drop the check for "up" being valid on suspend/resume callbacks.
It should be valid always. Get rid of the "pdata" check also as
serial_omap_get_context_loss_count() checks for it.

Tested on omap4 panda and 3630 based Beagle board.

Signed-off-by: Sourav Poddar <sourav.poddar@ti.com>
Reviewed-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>