Pass -flto to asflags as well

Although it has no effect, CFI mandates -flto in asflags.

Test: presubmit
Bug: 243476017
Change-Id: I33246488140c642894f3fbab65bc37bdd5de3024

cc/lto.go

@@ -101,6 +101,7 @@ func (lto *lto) flags(ctx BaseModuleContext, flags Flags) Flags {
 		}
 
 		flags.Local.CFlags = append(flags.Local.CFlags, ltoCFlag)
+		flags.Local.AsFlags = append(flags.Local.AsFlags, ltoCFlag)
 		flags.Local.LdFlags = append(flags.Local.LdFlags, ltoCFlag)
 		flags.Local.LdFlags = append(flags.Local.LdFlags, ltoLdFlag)