tty: serial: msm_geni_serial: Handle RX errors and statistics

Currently when RX errors like parity/framing errors happen or break event
happens then the driver clears the IRQ status bits without handling the
data. The stale data inside the serial engine prevents further data
from being handled. This leaves the RX state machine in bad state.

Handle the RX errors by handling the data and drop it depending on the
error. Maintain the error statistics and log appropriately.

CRs-Fixed: 2061543
Change-Id: If2dbc57c9799ca7d13b30e837bfba457494f304a
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@codeaurora.org>