build-env.sh: Switch to dt-schema v2025.12

Switch to v2025.12 release of dt-schema.

Signed-off-by: Nishanth Menon <nm@ti.com>

Author: nmenon

build-env.sh

@@ -14,7 +14,7 @@ export SPARSE_TAG=master
 # https://repo.or.cz/smatch.git
 export SMATCH_TAG=master
 # https://github.com/devicetree-org/dt-schema/tags
-export DTSCHEMA_REV=master
+export DTSCHEMA_REV=v2025.12
 
 ARIA_OPTS=( --summary-interval=5 --timeout=180 --retry-wait=10 -m 0 -x 10 -j 10 )
 # Get latest pip and packages in the "virtual env"