Refactored code to support INSTANCES as string

Modified code in meson build to support INSTANCES flag as string
type which is passed from machine layer bb file.

Tested: Tested and verified the INSTANCES value.

Signed-off-by: Jayashree Dhanapal <jayashree-d@hcl.com>
Change-Id: I91a7610157c30abf2cbc4783350d8b0a744a6ba9
diff --git a/src/usb-dbg.cpp b/src/usb-dbg.cpp
index 3579ef1..7b76310 100644
--- a/src/usb-dbg.cpp
+++ b/src/usb-dbg.cpp
@@ -15,6 +15,7 @@
  */
 
 #include <usb-dbg.hpp>
+#include <commandutils.hpp>
 
 namespace ipmi
 {
@@ -943,7 +944,7 @@
             hostPosition = getSelectorPosition();
         }
 
-        if (hostPosition == BMC_POSITION || INSTANCES == "0")
+        if (hostPosition == BMC_POSITION || hostInstances == "0")
         {
             frame_info.append("FRU:spb", 0);
         }