AP_Filesystem: avoid ff.h in header

this avoids the chibios hal includes

libraries/AP_Filesystem/AP_Filesystem.h

@@ -24,21 +24,24 @@
 
 #include "AP_Filesystem_Available.h"
 
+#ifndef MAX_NAME_LEN
+#define MAX_NAME_LEN 255
+#endif
+
 #if CONFIG_HAL_BOARD == HAL_BOARD_CHIBIOS
 #if HAVE_FILESYSTEM_SUPPORT
 #include "AP_Filesystem_FATFS.h"
 #endif
 #define DT_REG 0
 #define DT_DIR 1
-#if defined(FF_MAX_LFN) && FF_USE_LFN != 0
-#define MAX_NAME_LEN FF_MAX_LFN 
-#else
-#define MAX_NAME_LEN 13
-#endif
+
 struct dirent {
    char    d_name[MAX_NAME_LEN]; /* filename */
    uint8_t d_type;
 };
+
+#endif // HAL_BOARD_CHIBIOS
+
 #include <fcntl.h>
 #include <errno.h>
 #include <unistd.h>
@@ -46,10 +49,12 @@ struct dirent {
 #ifndef AP_FILESYSTEM_FORMAT_ENABLED
 // only enable for SDMMC filesystems for now as other types can't query
 // block size
-#define AP_FILESYSTEM_FORMAT_ENABLED (STM32_SDC_USE_SDMMC1==TRUE || STM32_SDC_USE_SDMMC2==TRUE)
+#ifndef HAL_USE_SDMMC
+#define HAL_USE_SDMMC 0
+#endif
+#define AP_FILESYSTEM_FORMAT_ENABLED HAL_USE_SDMMC
 #endif
 
-#endif // HAL_BOARD_CHIBIOS
 #if CONFIG_HAL_BOARD == HAL_BOARD_LINUX || CONFIG_HAL_BOARD == HAL_BOARD_SITL
 #include "AP_Filesystem_posix.h"
 #endif

libraries/AP_Filesystem/AP_Filesystem_FATFS.cpp

@@ -9,6 +9,7 @@
 
 #if HAVE_FILESYSTEM_SUPPORT && CONFIG_HAL_BOARD == HAL_BOARD_CHIBIOS
 
+#include <ff.h>
 #include <AP_HAL_ChibiOS/sdcard.h>
 #include <GCS_MAVLink/GCS.h>
 

libraries/AP_Filesystem/AP_Filesystem_FATFS.h

@@ -9,7 +9,6 @@
 #include <fcntl.h>
 #include <errno.h>
 #include <stddef.h>
-#include <ff.h>
 #include "AP_Filesystem_backend.h"
 
 // Seek offset macros
@@ -17,12 +16,6 @@
 #define SEEK_CUR 1
 #define SEEK_END 2
 
-#if FF_USE_LFN != 0
-#define MAX_NAME_LEN FF_MAX_LFN 
-#else
-#define MAX_NAME_LEN 13
-#endif
-
 class AP_Filesystem_FATFS : public AP_Filesystem_Backend
 {
 public: