mmc: fix broken if clause

Fix a broken if clause which was causing SD cards to go into
4-bit mode even if the host did not support it.

(Reported by David Brownell and Marc Pignat)

Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index c1dfd03..5afac20 100644
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -402,7 +402,7 @@
 	/*
 	 * Switch to wider bus (if supported).
 	 */
-	if ((host->caps && MMC_CAP_4_BIT_DATA) &&
+	if ((host->caps & MMC_CAP_4_BIT_DATA) &&
 		(card->scr.bus_widths & SD_SCR_BUS_WIDTH_4)) {
 		err = mmc_app_set_bus_width(card, MMC_BUS_WIDTH_4);
 		if (err != MMC_ERR_NONE)