Use thiserror in pVM firmware.

Test: m pvmfw
Change-Id: Ib98435fadff21754166b9187941a3e2d265082e6

diff --git a/libs/libhypervisor_backends/Android.bp b/libs/libhypervisor_backends/Android.bp
index b001b8f..27e3fe5 100644
--- a/libs/libhypervisor_backends/Android.bp
+++ b/libs/libhypervisor_backends/Android.bp
@@ -14,6 +14,7 @@
     rustlibs: [
         "libonce_cell_nostd",
         "libsmccc",
+        "libthiserror_nostd",
         "libuuid_nostd",
     ],
     enabled: false,