build: Configure stripping via target.json

We should only be setting linker flags in one place.

Signed-off-by: Joe Richey <joerichey@google.com>

Author: josephlr

.cargo/config

@@ -14,6 +14,7 @@
   "features": "-mmx,-sse,+soft-float",
   "pre-link-args": {
     "ld.lld": [
+      "-s",
       "--script=layout.ld"
     ]
   }