MAINTAINERS: Add maintainers for MIPS core drivers

Add Thomas and myself as maintainers of the MIPS CPU and GIC IRQchip, MIPS
GIC timer and MIPS CPS CPUidle drivers.

Signed-off-by: Serge Semin <[e-mail]>
Acked-by: Marc Zyngier <[e-mail]>
Acked-by: Daniel Lezcano <[e-mail]>
Signed-off-by: Thomas Bogendoerfer <[e-mail]>

MAINTAINERS

···
 F:	drivers/clk/imgtec/clk-boston.c
 F:	include/dt-bindings/clock/boston-clock.h
 
+MIPS CORE DRIVERS
+M:	Thomas Bogendoerfer <[e-mail]>
+M:	Serge Semin <[e-mail]>
+L:	[e-mail]
+S:	Supported
+F:	drivers/bus/mips_cdmm.c
+F:	drivers/clocksource/mips-gic-timer.c
+F:	drivers/cpuidle/cpuidle-cps.c
+F:	drivers/irqchip/irq-mips-cpu.c
+F:	drivers/irqchip/irq-mips-gic.c
+
 MIPS GENERIC PLATFORM
 M:	Paul Burton <[e-mail]>
 L:	[e-mail]