toolchain: move CONFIG_LLVM_USE_LD into cmake/toolchain/llvm

This moves CONFIG_LLVM_USE_LD into cmake/toolchain/llvm as this
is a toolchain kconfig. Also make it a choice to allow the use
of LLVM's lld as linker.

Signed-off-by: Daniel Leung <daniel.leung@intel.com>

Kconfig.zephyr

@@ -167,13 +167,6 @@ config CMAKE_LINKER_GENERATOR
 
 endchoice
 
-config LLVM_USE_LD
-	bool "LLVM use ld linker"
-	depends on "${ZEPHYR_TOOLCHAIN_VARIANT}" = "llvm"
-	default y
-	help
-	  Use binutils ld linker instead of LLVM built-in lld linker.
-
 config HAVE_CUSTOM_LINKER_SCRIPT
 	bool "Custom linker script provided"
 	help

cmake/toolchain/llvm/Kconfig

@@ -0,0 +1,19 @@
+# Copyright (c) 2023 Intel Corporation
+# SPDX-License-Identifier: Apache-2.0
+
+choice LLVM_LINKER
+	prompt "LLVM Linker"
+	depends on "${ZEPHYR_TOOLCHAIN_VARIANT}" = "llvm"
+	default LLVM_USE_LD
+
+config LLVM_USE_LD
+	bool "GNU ld"
+	help
+	  Use binutils ld linker with llvm/clang.
+
+config LLVM_USE_LLD
+	bool "LLVM lld"
+	help
+	  Use LLVM built-in lld linker with llvm/clang.
+
+endchoice

scripts/ci/check_compliance.py

@@ -623,6 +623,10 @@ flagged.
         "FOO_SETTING_1",
         "FOO_SETTING_2",
         "LSM6DSO_INT_PIN",
+        "LLVM_USE_LD",   # Both LLVM_USE_* are in cmake/toolchain/llvm/Kconfig
+        "LLVM_USE_LLD",  # which are only included if LLVM is selected but
+                         # not other toolchains. Compliance check would complain,
+                         # for example, if you are using GCC.
         "MCUBOOT_LOG_LEVEL_WRN",        # Used in example adjusting MCUboot
                                         # config,
         "MCUBOOT_DOWNGRADE_PREVENTION", # but symbols are defined in MCUboot