are available from port structure

Add missing uart regs to uart_port structure which can be used in
context restore. Store dll, dlh, mdr1, scr, efr, lcr, mcr reg values
into uart_port structure while configuring individual port in termios
function.

Signed-off-by: Govindraj.R <govindraj.raja@ti.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de> (for drivers/tty changes)
Signed-off-by: Kevin Hilman <khilman@ti.com>