MAINTAINERS: add spi support to GXP

Add the spi driver and dt-binding documentation
Signed-off-by: Nick Hawkins <nick.hawkins@hpe.com>
Link: https://lore.kernel.org/r/20220728161459.7738-6-nick.hawkins@hpe.comSigned-off-by: Mark Brown <broonie@kernel.org>

MAINTAINERS

@@ -2140,11 +2140,13 @@ M:	Jean-Marie Verdun <verdun@hpe.com>
 M:	Nick Hawkins <nick.hawkins@hpe.com>
 S:	Maintained
 F:	Documentation/devicetree/bindings/arm/hpe,gxp.yaml
+F:	Documentation/devicetree/bindings/spi/hpe,gxp-spi.yaml
 F:	Documentation/devicetree/bindings/timer/hpe,gxp-timer.yaml
 F:	arch/arm/boot/dts/hpe-bmc*
 F:	arch/arm/boot/dts/hpe-gxp*
 F:	arch/arm/mach-hpe/
 F:	drivers/clocksource/timer-gxp.c
+F:	drivers/spi/spi-gxp.c
 F:	drivers/watchdog/gxp-wdt.c
 
 ARM/IGEP MACHINE SUPPORT