MAINTAINERS: co-maintain LiteX platform

Add the litex_mmc (LiteSDCard) and LiteETH drivers to the list
of files maintained under LiteX.

Add Gabriel Somlo and Joel Stanley as maintainers; Joel authored
the LiteETH driver, and Gabriel is currently curating the LiteX
out-of-tree device drivers as they are tested and prepared for
upstream submission, having also co-authored a number of them.
Signed-off-by: Gabriel Somlo <gsomlo@gmail.com>
Acked-by: Joel Stanley <joel@jms.id.au>
Acked-by: Mateusz Holenko <mholenko@antmicro.com>
Link: https://lore.kernel.org/r/20220113170300.3555651-2-gsomlo@gmail.comSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>

MAINTAINERS

@@ -11130,12 +11130,17 @@ F:	lib/list-test.c
 LITEX PLATFORM
 M:	Karol Gugala <kgugala@antmicro.com>
 M:	Mateusz Holenko <mholenko@antmicro.com>
+M:	Gabriel Somlo <gsomlo@gmail.com>
+M:	Joel Stanley <joel@jms.id.au>
 S:	Maintained
 F:	Documentation/devicetree/bindings/*/litex,*.yaml
 F:	arch/openrisc/boot/dts/or1klitex.dts
-F:	drivers/soc/litex/litex_soc_ctrl.c
-F:	drivers/tty/serial/liteuart.c
 F:	include/linux/litex.h
+F:	drivers/tty/serial/liteuart.c
+F:	drivers/soc/litex/*
+F:	drivers/net/ethernet/litex/*
+F:	drivers/mmc/host/litex_mmc.c
+N:	litex
 
 LIVE PATCHING
 M:	Josh Poimboeuf <jpoimboe@redhat.com>