[DNM] mpsl: include mdk_config in hwres header

Target symbol definition has been move from CMake to
MDK config header. Include the header to get access to
defined symbols.

Signed-off-by: Michał Stasiak <michal.stasiak@nordicsemi.no>

Author: mstasiaknordic

mpsl/include/mpsl_hwres.h

@@ -17,6 +17,9 @@
 #ifndef MPSL_HWRES_H__
 #define MPSL_HWRES_H__
 
+/* Symbols passed to nrfx-based MDK. */
+#include <mdk_config.h>
+
 /*  The xx_SERIES macros are defined here to keep this file independent
     of the MDK. This allows the header file to be used in nrfx without
     creating circular dependencies. */