Remove redundant dependency

I accidentally noticed we don't use spinlock in pvmfw. And we probably
shouldn't, since it's single threaded. (Other than various parts of
vmbase which does have the dependency.)

Test: TH
Change-Id: Ib7c33b4d9bd7baf98d0e0ed2d8208cc20d2cf8d5
diff --git a/pvmfw/Android.bp b/pvmfw/Android.bp
index f49bbce..c6befb4 100644
--- a/pvmfw/Android.bp
+++ b/pvmfw/Android.bp
@@ -34,7 +34,6 @@
         "libvmbase",
         "libzerocopy_nostd",
         "libzeroize_nostd",
-        "libspin_nostd",
     ],
 }