FS_RAMMAP depends on FS_REFCOUNT and remove useless macro

Signed-off-by: zhangshoukui <zhangshoukui@xiaomi.com>

fs/mmap/Kconfig

@@ -6,6 +6,7 @@
 config FS_RAMMAP
 	bool "File mapping emulation"
 	default n
+	depends on FS_REFCOUNT
 	---help---
 		NuttX operates in a flat open address space and is focused on MCUs that do
 		support Memory Management Units (MMUs).  Therefore, NuttX generally does not

fs/mmap/fs_rammap.c

@@ -40,8 +40,6 @@
 #include "fs_rammap.h"
 #include "sched/sched.h"
 
-#ifdef CONFIG_FS_RAMMAP
-
 /****************************************************************************
  * Public Data
  ****************************************************************************/
@@ -347,5 +345,3 @@ errout_with_region:
 
   return ret;
 }
-
-#endif /* CONFIG_FS_RAMMAP */