tty: serial: msm_geni_serial: Capture buffer overrun in RX Direction

Update the buffer overrun statistics in the incoming direction and log the
updated statistics when the condition occurs.

Change-Id: Ic9a2119d0ada78a1c0f6948d14d33029e41aa59b
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@codeaurora.org>