MAINTAINERS: maintain qcs9100_defconfig

Add this to ARM SNAPDRAGON maintainers entry.

Signed-off-by: Caleb Connolly <caleb.connolly@linaro.org>
Link: https://lore.kernel.org/u-boot/20250122160951.1861910-1-caleb.connolly@linaro.org
diff --git a/MAINTAINERS b/MAINTAINERS
index ba31f86..5a575f4 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -631,6 +631,7 @@
 S:	Maintained
 T:	git https://source.denx.de/u-boot/custodians/u-boot-snapdragon.git
 F:	configs/qcm6490_defconfig
+F:	configs/qcs9100_defconfig
 F:	drivers/*/*/pm8???-*
 F:	drivers/gpio/msm_gpio.c
 F:	drivers/mmc/msm_sdhci.c