ci: set riscv64-linux timeouts to 6 hours

Author: alexrp

.github/workflows/riscv.yaml

@@ -5,15 +5,15 @@ permissions:
   contents: read
 jobs:
   riscv64-linux-debug:
-    timeout-minutes: 1020
+    timeout-minutes: 360
     runs-on: [self-hosted, Linux, riscv64]
     steps:
       - name: Checkout
         uses: actions/checkout@v4
       - name: Build and Test
         run: sh ci/riscv64-linux-debug.sh
   riscv64-linux-release:
-    timeout-minutes: 900
+    timeout-minutes: 360
     runs-on: [self-hosted, Linux, riscv64]
     steps:
       - name: Checkout