mmc: bcm2835_sdhci: Use calloc to allocate bcm2835_sdhci_host

We need to clear the allocated memory explicitly as the included
struct sdhci_host has function pointers. Those are compared to NULL to
test if this (optional) feature is supported. Leaving them undefined let
u-boot jump to arbitrary memory.

Signed-off-by: Alexander Stein <alexanders83@web.de>

drivers/mmc/bcm2835_sdhci.c

@@ -154,9 +154,9 @@ int bcm2835_sdhci_init(u32 regbase, u32 emmc_freq)
 	struct bcm2835_sdhci_host *bcm_host;
 	struct sdhci_host *host;
 
-	bcm_host = malloc(sizeof(*bcm_host));
+	bcm_host = calloc(1, sizeof(*bcm_host));
 	if (!bcm_host) {
-		printf("sdhci_host malloc fail!\n");
+		printf("sdhci_host calloc fail!\n");
 		return 1;
 	}