Regression: serial: imx: overrun errors on debug UART

[Stefan Wahren]

Hi,

after switching to Linux 6.1.21 on our Tarragon board (i.MX6ULL SoC), we 
experience the following issues with the debug UART (115200 baud, 8N1, 
no hardware flow control):

- overrun errors if we paste in multiple text lines while system is idle
- no reaction to single key strokes while system is on higher load

After reverting 7a637784d517 ("serial: imx: reduce RX interrupt 
frequency") the issue disappear.

Maybe it's worth to mention that the Tarragon board uses two additional 
application UARTs with similiar baud rates (9600 - 115200 baud, no 
hardware flow control) for RS485 communication, but there are no overrun 
errors (with and without the mention change).

Best regards