AP_HAL_ChibiOS: replace HAVE_FILESYSTEM_SUPPORT with backend defines

libraries/AP_HAL_ChibiOS/hwdef/scripts/chibios_hwdef.py

@@ -3251,6 +3251,10 @@ INCLUDE common.ld
 #define HAL_SPEKTRUM_TELEM_ENABLED 0
 #endif
 
+#ifndef AP_FILESYSTEM_ROMFS_ENABLED
+#define AP_FILESYSTEM_ROMFS_ENABLED 0
+#endif
+
 // end AP_Periph defaults
 ''')
 

libraries/AP_HAL_ChibiOS/sdcard.cpp

@@ -184,7 +184,7 @@ bool sdcard_retry(void)
 #ifdef USE_POSIX
     if (!sdcard_running) {
         if (sdcard_init()) {
-#if HAVE_FILESYSTEM_SUPPORT
+#if AP_FILESYSTEM_FILE_WRITING_ENABLED
             // create APM directory
             AP::FS().mkdir("/APM");
 #endif