M5Stack sdcard cleanup (#72)

boards/m5stack_cores3/source/m5stack_cores3.c

@@ -1,12 +1,14 @@
 #include "m5stack_cores3.h"
 #include "m5stack_shared.h"
 
+extern const SdCard m5stack_cores3_sdcard;
+
 const HardwareConfig m5stack_cores3 = {
     .bootstrap = &m5stack_bootstrap,
     .display = {
         .set_backlight_duty = NULL
     },
     .init_graphics = &m5stack_lvgl_init,
-    .sdcard = &m5stack_sdcard,
+    .sdcard = &m5stack_cores3_sdcard,
     .power = &m5stack_power
 };

boards/m5stack_cores3/source/m5stack_cores3_sdcard.c

@@ -71,7 +71,7 @@ static bool sdcard_is_mounted(void* context) {
     return (data != NULL) && (sdmmc_get_status(data->card) == ESP_OK);
 }
 
-const SdCard m5stack_sdcard = {
+const SdCard m5stack_cores3_sdcard = {
     .mount = &sdcard_mount,
     .unmount = &sdcard_unmount,
     .is_mounted = &sdcard_is_mounted,

boards/m5stack_shared/src/m5stack_shared.h

@@ -11,7 +11,6 @@ extern bool m5stack_lvgl_init();
 extern bool m5stack_bootstrap();
 
 extern Power m5stack_power;
-extern const SdCard m5stack_sdcard;
 
 #ifdef __cplusplus
 }