Condition the print load systemlib build correctly for all OS

src/modules/systemlib/module.mk

@@ -57,11 +57,12 @@ ifeq ($(PX4_TARGET_OS),nuttx)
 SRCS		+= err.c \
 		   printload.c \
 		   up_cxxinitialize.c 
+else
+SRCS		+= print_load_posix.c
 endif
 
 ifneq ($(PX4_TARGET_OS),qurt)
-SRCS 		+= hx_stream.c \
-		   print_load_posix.c
+SRCS 		+= hx_stream.c
 endif
 
 MAXOPTIMIZATION	 = -Os

src/modules/systemlib/print_load_posix.c

@@ -32,7 +32,7 @@
  ****************************************************************************/
 
 /**
- * @file printload.c
+ * @file print_load_posix.c
  *
  * Print the current system load.
  *