mmc: Split mmc struct, rework mmc initialization (v2)

The way that struct mmc was implemented was a bit of a mess;
configuration and internal state all jumbled up in a single structure.

On top of that the way initialization is done with mmc_register leads
to a lot of duplicated code in drivers.

Typically the initialization got something like this in every driver.

	struct mmc *mmc = malloc(sizeof(struct mmc));
	memset(mmc, 0, sizeof(struct mmc);
	/* fill in fields of mmc struct */
	/* store private data pointer */
	mmc_register(mmc);

By using the new mmc_create call one just passes an mmc config struct
and an optional private data pointer like this:

	struct mmc = mmc_create(&cfg, priv);

All in tree drivers have been updated to the new form, and expect
mmc_register to go away before long.

Changes since v1:

* Use calloc instead of manually calling memset.
* Mark mmc_register as deprecated.

Signed-off-by: Pantelis Antoniou <panto@antoniou-consulting.com>
diff --git a/common/cmd_mmc.c b/common/cmd_mmc.c
index 2d51927..bd1edc8 100644
--- a/common/cmd_mmc.c
+++ b/common/cmd_mmc.c
@@ -79,7 +79,7 @@
 };
 static void print_mmcinfo(struct mmc *mmc)
 {
-	printf("Device: %s\n", mmc->name);
+	printf("Device: %s\n", mmc->cfg->name);
 	printf("Manufacturer ID: %x\n", mmc->cid[0] >> 24);
 	printf("OEM: %x\n", (mmc->cid[0] >> 8) & 0xffff);
 	printf("Name: %c%c%c%c%c \n", mmc->cid[0] & 0xff,