qcacmn: Cleanup CONFIG_MCL for qdf_mem.c

Remove CONFIG_MCL and include the header file for both MCL and
WIN code since this feature is already handled by the feature macro
FEATURE_WLAN_DIAG_SUPPORT.

Change-Id: I4d4ed46ed5cb62950bb8b25af0a173bfe5f86474
CRs-Fixed: 2399386

qdf/linux/src/qdf_mem.c

@@ -35,12 +35,6 @@
 #include <linux/seq_file.h>
 #include <linux/string.h>
 
-#ifdef CONFIG_MCL
-#include <host_diag_core_event.h>
-#else
-#define host_log_low_resource_failure(code) do {} while (0)
-#endif
-
 #if defined(CONFIG_CNSS)
 #include <net/cnss.h>
 #endif