dirvers: mmc: use __weak

use weak instead of alias to prevent some clang warnings.
Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>

drivers/mmc/mmc.c

@@ -42,13 +42,11 @@ int mmc_getwp(struct mmc *mmc)
 	return wp;
 }
 
-int __board_mmc_getcd(struct mmc *mmc) {
+__weak int board_mmc_getcd(struct mmc *mmc)
+{
 	return -1;
 }
 
-int board_mmc_getcd(struct mmc *mmc)__attribute__((weak,
-	alias("__board_mmc_getcd")));
-
 int mmc_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd, struct mmc_data *data)
 {
 	int ret;
@@ -1371,17 +1369,17 @@ int mmc_set_dsr(struct mmc *mmc, u16 val)
 	return 0;
 }
 
-/*
- * CPU and board-specific MMC initializations.  Aliased function
- * signals caller to move on
- */
-static int __def_mmc_init(bd_t *bis)
+/* CPU-specific MMC initializations */
+__weak int cpu_mmc_init(bd_t *bis)
 {
 	return -1;
 }
 
-int cpu_mmc_init(bd_t *bis) __attribute__((weak, alias("__def_mmc_init")));
-int board_mmc_init(bd_t *bis) __attribute__((weak, alias("__def_mmc_init")));
+/* board-specific MMC initializations. */
+__weak int board_mmc_init(bd_t *bis)
+{
+	return -1;
+}
 
 #if !defined(CONFIG_SPL_BUILD) || defined(CONFIG_SPL_LIBCOMMON_SUPPORT)