MAINTAINERS: Add entry for the ASPEED SD/MMC driver

Add myself as the maintainer.

Signed-off-by: Andrew Jeffery <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Ulf Hansson <[e-mail]>

MAINTAINERS

···
 F:	drivers/irqchip/irq-aspeed-scu-ic.c
 F:	include/dt-bindings/interrupt-controller/aspeed-scu-ic.h
 
+ASPEED SD/MMC DRIVER
+M:	Andrew Jeffery <[e-mail]>
+L:	[e-mail] (moderated for non-subscribers)
+L:	[e-mail] (moderated for non-subscribers)
+L:	[e-mail]
+S:	Maintained
+F:	Documentation/devicetree/bindings/mmc/aspeed,sdhci.yaml
+F:	drivers/mmc/host/sdhci-of-aspeed*
+
 ASPEED VIDEO ENGINE DRIVER
 M:	Eddie James <[e-mail]>
 L:	[e-mail]