MAINTAINERS: Add myself as designated reviewer for 8250_dw

It happened several times that some odd fixes either introduced
regressions, or did hack the code instead of addressing a root cause.

Nominate myself to be a designated reviewer for 8250_dw driver.

Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: Lukas Wunner <lukas@wunner.de>
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

MAINTAINERS

@@ -13098,6 +13098,11 @@ S:	Supported
 F:	drivers/reset/reset-axs10x.c
 F:	Documentation/devicetree/bindings/reset/snps,axs10x-reset.txt
 
+SYNOPSYS DESIGNWARE 8250 UART DRIVER
+R:	Andy Shevchenko <andriy.shevchenko@linux.intel.com>
+S:	Maintained
+F:	drivers/tty/serial/8250/8250_dw.c
+
 SYNOPSYS DESIGNWARE APB GPIO DRIVER
 M:	Hoan Tran <hotran@apm.com>
 L:	linux-gpio@vger.kernel.org