qcacld-3.0: fix creating proc directory issue for multiple chips

When using multiple chips, PREFIX is defined as '<chip_name>/',
proc_mkdir function can't create sub directory, fix the issue to
create directory with '/proc/<chip_name>_debugdriver'.

Change-Id: Id70077247401f5b92ff5c72c813c955e1cf5feb7
CRs-Fixed: 3305100

core/hdd/src/wlan_hdd_memdump.c

@@ -34,9 +34,9 @@
 #include <wlan_hdd_includes.h>
 
 #if defined(DYNAMIC_SINGLE_CHIP)
-#define PREFIX DYNAMIC_SINGLE_CHIP "/"
+#define PREFIX DYNAMIC_SINGLE_CHIP "_"
 #elif defined(MULTI_IF_NAME)
-#define PREFIX MULTI_IF_NAME "/"
+#define PREFIX MULTI_IF_NAME "_"
 #else
 #define PREFIX ""
 #endif