CMake: unit-tests: Move mbed-headers-drivers to the drivers directory

Move the header-only mbed-headers-drivers library the unit test stubs
depend on into the drivers component directory. This makes the drivers
stubs more self-contained and improves the composition of the library.

Author: rajkan01

UNITTESTS/stubs/CMakeLists.txt

@@ -7,7 +7,6 @@ add_library(mbed-headers-base INTERFACE)
 add_library(mbed-headers-platform INTERFACE)
 add_library(mbed-headers-connectivity INTERFACE)
 add_library(mbed-headers-storage INTERFACE)
-add_library(mbed-headers-drivers INTERFACE)
 add_library(mbed-headers-hal INTERFACE)
 add_library(mbed-headers-events INTERFACE)
 add_library(mbed-headers-rtos INTERFACE)
@@ -87,13 +86,6 @@ target_include_directories(mbed-headers-connectivity
         ${mbed-os_SOURCE_DIR}/connectivity/FEATURE_BLE/include/ble
 )
 
-target_include_directories(mbed-headers-drivers
-    INTERFACE
-        ${mbed-os_SOURCE_DIR}/drivers
-        ${mbed-os_SOURCE_DIR}/drivers/include
-        ${mbed-os_SOURCE_DIR}/drivers/include/drivers
-)
-
 target_include_directories(mbed-headers-events
     INTERFACE
         ${mbed-os_SOURCE_DIR}/events/tests/UNITTESTS/target_h

drivers/tests/UNITTESTS/doubles/CMakeLists.txt

@@ -1,6 +1,15 @@
 # Copyright (c) 2021 ARM Limited. All rights reserved.
 # SPDX-License-Identifier: Apache-2.0
 
+add_library(mbed-headers-drivers INTERFACE)
+
+target_include_directories(mbed-headers-drivers
+    INTERFACE
+        ${mbed-os_SOURCE_DIR}/drivers
+        ${mbed-os_SOURCE_DIR}/drivers/include
+        ${mbed-os_SOURCE_DIR}/drivers/include/drivers
+)
+
 add_library(mbed-stubs-drivers)
 
 target_sources(mbed-stubs-drivers