fix: riscv64 QEMU uses qemu-system-misc, not qemu-system-mips

Author: srpatcha

.github/workflows/qemu-test.yml

@@ -99,7 +99,7 @@ jobs:
             qemu: qemu-system-riscv64
             machine: virt
             cpu: rv64
-            pkg: qemu-system-mips
+            pkg: qemu-system-misc
           - arch: mipsel
             qemu: qemu-system-mipsel
             machine: malta