serial: msm_geni_serial: Bailout from suspend if RX data is pending

This change is to resolve potential race btw stop rx and cancel rx
due to interrupt latency in the system.

Change-Id: I7b510949f75bac5ec9f8f42f3d139131b259600f
Signed-off-by: Chandana Kishori Chiluveru <cchiluve@codeaurora.org>