mmc: constify mmc_host_ops vectors

Now that mmc_host_ops can be constified, update the various drivers
to constify those method tables and shrink the writable data segment.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
diff --git a/drivers/mmc/sdhci.c b/drivers/mmc/sdhci.c
index 9a7d39b..54990ed 100644
--- a/drivers/mmc/sdhci.c
+++ b/drivers/mmc/sdhci.c
@@ -784,7 +784,7 @@
 	return !(present & SDHCI_WRITE_PROTECT);
 }
 
-static struct mmc_host_ops sdhci_ops = {
+static const struct mmc_host_ops sdhci_ops = {
 	.request	= sdhci_request,
 	.set_ios	= sdhci_set_ios,
 	.get_ro		= sdhci_get_ro,