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/toolchain/llvm-efi/BUILD.bazel b/build/toolchain/llvm-efi/BUILD.bazel
index 66204db..9bce651 100644
--- a/build/toolchain/llvm-efi/BUILD.bazel
+++ b/build/toolchain/llvm-efi/BUILD.bazel
@@ -39,7 +39,7 @@
     ],
     target_compatible_with = [
         "@platforms//cpu:x86_64",
-        "//build/platforms/os:efi",
+        "@platforms//os:uefi",
     ],
     toolchain = ":efi_k8_cc_toolchain",
     toolchain_type = "@bazel_tools//tools/cpp:toolchain_type",