build: upstream UEFI to platforms

This removes our local UEFI constraint_value for a patch sent upstream
to @platforms. This will be used by rules_rust in a follow-up.

Change-Id: I16e3bf8a60923a2f77ef036babdda45205d8a078
Reviewed-on: https://review.monogon.dev/c/monogon/+/2103
Tested-by: Jenkins CI
Reviewed-by: Serge Bazanski <serge@monogon.tech>
diff --git a/build/platforms/BUILD.bazel b/build/platforms/BUILD.bazel
index e612a9c..20cf3cd 100644
--- a/build/platforms/BUILD.bazel
+++ b/build/platforms/BUILD.bazel
@@ -11,7 +11,7 @@
 platform(
     name = "efi_amd64",
     constraint_values = [
-        "//build/platforms/os:efi",
+        "@platforms//os:uefi",
         "@platforms//cpu:x86_64",
     ],
 )