MAINTAINERS: Add maintainer of DW APB SSI driver

Add myself as a maintainer of the Synopsis DesignWare APB SSI driver.
Suggested-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20201002211648.24320-1-Sergey.Semin@baikalelectronics.ruSigned-off-by: Mark Brown <broonie@kernel.org>

MAINTAINERS

@@ -16479,6 +16479,13 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/gpio/snps,dw-apb-gpio.yaml
 F:	drivers/gpio/gpio-dwapb.c
 
+SYNOPSYS DESIGNWARE APB SSI DRIVER
+M:	Serge Semin <fancer.lancer@gmail.com>
+L:	linux-spi@vger.kernel.org
+S:	Supported
+F:	Documentation/devicetree/bindings/spi/snps,dw-apb-ssi.yaml
+F:	drivers/spi/spi-dw*
+
 SYNOPSYS DESIGNWARE AXI DMAC DRIVER
 M:	Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
 S:	Maintained