msm_serial_hs_lite: Add support of loopback mode for each uart port

This change allows to use debugfs entry called loopback.uart_id to
enable/disable uartdm internal loopback mode.
e.g. for /dev/ttyHSL0 device,
it creates <debugfs_dir>/msm_serial_hsl/loopback.0

Signed-off-by: Mayank Rana <mrana@codeaurora.org>
1 file changed