fixed SConstruct file spell error in imxrt1064-nxp-evk

bsp/imxrt/imxrt1064-nxp-evk/SConstruct

@@ -46,10 +46,10 @@ Export('RTT_ROOT')
 Export('rtconfig')
 
 SDK_ROOT = os.path.abspath('./')
-if os.path.exists(SDK_ROOT + '/Libraries'):
-    libraries_path_prefix = SDK_ROOT + '/Libraries'
+if os.path.exists(SDK_ROOT + '/libraries'):
+    libraries_path_prefix = SDK_ROOT + '/libraries'
 else:
-    libraries_path_prefix = os.path.dirname(SDK_ROOT) + '/Libraries'
+    libraries_path_prefix = os.path.dirname(SDK_ROOT) + '/libraries'
 
 SDK_LIB = libraries_path_prefix
 Export('SDK_LIB')