serial: msm_geni_serial: Reduce wait for transfer delay

This is to reduce wait for transfer delay which is introducing
total 20msec delay during port_close()/BT off usecase.

Also added other debug logs required in this change.

Change-Id: Ia1135b097e6b9137ee3fb9504b2d8c29c05dbab3
Signed-off-by: Chandana Kishori Chiluveru <cchiluve@codeaurora.org>