MAINTAINERS: Add missed files related to Synopsys DesignWare UART

8250_dw has been split to library part and the driver, the library
is being used by 8250_lpss, which represents Synosys DesignWare UART
(with optional Synopsys Designware DMA) enumerated by PCI.

Add missed above mentioned files to the database record for review.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200305123108.41320-1-andriy.shevchenko@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

MAINTAINERS

@@ -16083,6 +16083,8 @@ SYNOPSYS DESIGNWARE 8250 UART DRIVER
 R:	Andy Shevchenko <andriy.shevchenko@linux.intel.com>
 S:	Maintained
 F:	drivers/tty/serial/8250/8250_dw.c
+F:	drivers/tty/serial/8250/8250_dwlib.*
+F:	drivers/tty/serial/8250/8250_lpss.c
 
 SYNOPSYS DESIGNWARE APB GPIO DRIVER
 M:	Hoan Tran <hoan@os.amperecomputing.com>