typo that wasn't caught by the compiler led to unexpected sharing

caught by asharing/mscan.

typo that wasn't caught by the compiler led to unexpected sharing
893091a1 · Nickolai Zeldovich · e131aa26 · 893091a1
--- a/kernel/rnd.cc
+++ b/kernel/rnd.cc
@@ -3,7 +3,7 @@
 struct seed {
  u64 v;
-} __mapalign__;
+} __mpalign__;
 static struct seed seeds[NCPU] __mpalign__;
 u64