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/pxamci.c b/drivers/mmc/pxamci.c
index a526698..471e9f4 100644
--- a/drivers/mmc/pxamci.c
+++ b/drivers/mmc/pxamci.c
@@ -393,7 +393,7 @@
 		 host->clkrt, host->cmdat);
 }
 
-static struct mmc_host_ops pxamci_ops = {
+static const struct mmc_host_ops pxamci_ops = {
 	.request	= pxamci_request,
 	.get_ro		= pxamci_get_ro,
 	.set_ios	= pxamci_set_ios,