vmbase: Provide baremetal DiceClearMemory() as lib

As libdiced_open_dice_nostd has a missing symbol, DiceClearMemory(),
that must be provided at link time, export it for all (baremetal)
clients of vmbase as a static library to be linked into their
final executable.

Link it into pvmfw and Rialto and remove their duped implementations.

Bug: 357008987
Test: m libvmbase_dice_clear_memory pvmfw_bin rialto_bin
Change-Id: I8d28e0ec11e1407c71de3e8f5c75069389151141
diff --git a/guest/rialto/Android.bp b/guest/rialto/Android.bp
index 8afb8ba..a525168 100644
--- a/guest/rialto/Android.bp
+++ b/guest/rialto/Android.bp
@@ -35,6 +35,7 @@
     ],
     static_libs: [
         "librialto",
+        "libvmbase_dice_clear_memory",
     ],
     linker_scripts: [
         "image.ld",