env: mmc/fat/ext4: undefined reference to `mmc_initialize'

For CONFIG_ENV_FAT_INTERFACE != 'mmc' a link error
env/fat.c:93: undefined reference to `mmc_initialize'
occurs if CONFIG_MMC_SUPPORT is not enabled.

Fixes: 26862b4a ("env: mmc/fat/ext4: make sure that the MMC sub-system
is initialized before using it")
Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>

env/ext4.c

@@ -87,8 +87,10 @@ static int env_ext4_load(void)
 	int err;
 	loff_t off;
 
+#ifdef CONFIG_MMC
 	if (!strcmp(CONFIG_ENV_EXT4_INTERFACE, "mmc"))
 		mmc_initialize(NULL);
+#endif
 
 	part = blk_get_device_part_str(CONFIG_ENV_EXT4_INTERFACE,
 				       CONFIG_ENV_EXT4_DEVICE_AND_PART,

env/fat.c

@@ -89,8 +89,10 @@ static int env_fat_load(void)
 	int dev, part;
 	int err;
 
+#ifdef CONFIG_MMC
 	if (!strcmp(CONFIG_ENV_FAT_INTERFACE, "mmc"))
 		mmc_initialize(NULL);
+#endif
 
 	part = blk_get_device_part_str(CONFIG_ENV_FAT_INTERFACE,
 					CONFIG_ENV_FAT_DEVICE_AND_PART,