MAINTAINERS: merge TRIGGER SOURCE sections

Merge all of Documentation/devicetree/bindings/trigger-source/* as a
single entry.

In the previous merge cycle, there was a merge conflict between the IIO
and SPI trees and we ended up with the current state, but the intention
was to have a single entry for all trigger-source bindings.

Signed-off-by: David Lechner <dlechner@baylibre.com>
Link: https://patch.msgid.link/20250815-spi-offload-trigger-followup-v1-1-8ec5413a8383@baylibre.com
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: dlech

MAINTAINERS

@@ -25601,16 +25601,10 @@ W:	https://github.com/srcres258/linux-doc
 T:	git https://github.com/srcres258/linux-doc.git doc-zh-tw
 F:	Documentation/translations/zh_TW/
 
-TRIGGER SOURCE - ADI UTIL SIGMA DELTA SPI
-M:	David Lechner <dlechner@baylibre.com>
-S:	Maintained
-F:	Documentation/devicetree/bindings/trigger-source/adi,util-sigma-delta-spi.yaml
-
 TRIGGER SOURCE
 M:	David Lechner <dlechner@baylibre.com>
 S:	Maintained
-F:	Documentation/devicetree/bindings/trigger-source/gpio-trigger.yaml
-F:	Documentation/devicetree/bindings/trigger-source/pwm-trigger.yaml
+F:	Documentation/devicetree/bindings/trigger-source/*
 
 TRUSTED SECURITY MODULE (TSM) INFRASTRUCTURE
 M:	Dan Williams <dan.j.williams@intel.com>